swim pool society

Overview

There are three elements of pool care that provide clean and clear water. These  are:

1.     Filtration and circulation

2.     Chemical and mineral components

3.     Sanitization and algae control

The water may contain naturally occurring minerals that can stain pool surfaces and / or calcium that can cause cloudy water or scale. These contaminants will require chemical treatment. Furthermore, pool water will be contaminated by rain, wind-blown dust and phosphates from farm fields, and swimmers body fluids and perfumes. Pools need to be filtered.

 

Filtration and circulation

Proper Cleaning and Filtration:

Keeping the pool and surrounding area clean from organic debris is fundamental to maintaining a healthy pool environment. Proper filtration requires that the pool pump and filter are in good operating condition; the pump and filter are running long enough daily; and water is circulating effectively. A clean pool will minimize water chemistry problems.

1.) Wash the pools waterline as necessary to remove built up oils and mineral deposits. There are many brands of over the counter tile and vinyl cleaners for this.

2.) Remove debris from skimmer basket(s), and pump trap basket as necessary, (never operate your pool pump without these in place; they are your only defense against plugged lines and or pump impeller). Use hand held skimmer net and pole to quickly remove floating debris from the pool.

3.) Vacuum Pool as necessary:

When vacuuming, your pool filters multi-port valve, (mpv.), should be set to the filter/vacuum to pool position for ordinary cleaning. If the pool has a large amount of fine debris, such as when vacuuming a freshly opened pool that had a mesh safety winter cover, set the mpv. to the drain/vacuum to waste position. This allows you to quickly remove fine debris without having to constantly backwash the filter; you must realize that when the mpv. is set in the drain/vacuum to waste position you have a finite amount of time to vacuum before the water level falls too low to continue vacuuming, at which point you need to add more water to the pool before continuing.

a.) close all suction lines, (main drain, second skimmer, deep water outlet, etc.), except for the skimmer you will use to vacuum.

b.) attach vacuum head to vacuum pole, attach swiveling end of vacuum hose to vacuum head, connect other end of vacuum hose to vacuum plate.

c.) Place the vacuum head into the pool and fill the vacuum hose with water by either holding the hose end with vacuum plate over a return inlet or by feeding the vacuum hose down into the pool starting with the vacuum head until you get to the vacuum plate, (you should see water come up through the hose if done properly).

d.) In a swift motion take the end of the hose with the vacuum plate on and place it down into the skimmer through the lid opening; be sure to position the vacuum plate so that it is centered over the skimmer basket. Never vacuum the pool without the skimmer basket in place; it is necessary to catch leaves and other large debris to avoid a potential plugged circulation line.

e.) Begin vacuuming the pool in a smooth steady motion. Begin in the shallowest portion of the pool and work methodically towards the deepest area. If during the vacuuming process the vacuum rate begins to slow, (i.e. you are having trouble picking up debris), this is a sign that the filter may be getting plugged. Check the filter pressure and if necessary clean the filter; otherwise look for an obstruction in the vacuum head, hose, skimmer basket, or pump trap basket and remove it. Do not lift the vacuum head out of the water while vacuuming as this will allow air to be drawn into the pool pump causing it to lose its prime.

f.) When finished, turn off the pool pump, remove vacuum hose and plate from the skimmer, empty skimmer basket and pump trap basket if necessary, backwash or clean filter if necessary, otherwise turn pump back on leaving the mpv. set in the filter/vacuum to pool position.

4.) Clean pool filter when necessary:

It is necessary to clean your filter when the filter pressure rises to a value that is 5-10 psi. greater than the filter pressure when it is clean, (just after cleaning). For instance lets say you just cleaned your filter, you turn the pump back on and the clean filter pressure is 12 psi., and the manufacturer suggests cleaning the filter when the pressure rises 10 psi.. You do not need to clean your filter until the filter pressure has risen to a value of 22 psi. It is important to clean the filter promptly when the pressure has risen to this point; allowing the pressure to build higher will result in poor circulation that may cause water chemistry problems, unsanitary water or your pool heater may not turn on. Equally important is that you not clean the filter before it has reached the 10 psi. threshold. As the filter pressure rises, your filter is slowly becoming a finer filter, allowing it to remove smaller and smaller debris particles. Using our previous example the filter will be a finer filter at 20psi. than at 15 psi. thereby removing more debris at a filter pressure of 20 psi.. If you constantly clean your filter before it has risen to the 10 psi. threshold, you may never experience the crystal clear pool water your filter is capable of producing. You will also have a harder time clearing cloudy pool water when necessary.

 

Filter Types:

Filtration is the mechanical cleaning of the pool water. It is the number 1 important element in keeping your pool clean and clear. A proper filter and pump must be able remove particles of dirt and debris caused by the environment and by bathers. A filter will clear cloudy water caused by chemical imbalance and suspended matter in the water. Three common types are:

1. Cartridge filters consist of pleated fabric, typically polyester, arranged in a cylinder form around a rigid core. The fibers of the polyester trap dirt and oils as the water passes through from around the outside of the cylinder and is returned back through to the pool from the center core. They are common in above ground and smaller residential pool applications because they are easy to operate and easily replaced if damaged or worn out. Cartridge filters will give longer service if they kept clean. Regular rinsing of the cartridge will help in removing large debris and there are spray-on cleaners specially formulated to help remove oily buildup not otherwise removed by simple rinsing with water alone. Periodic deep cleaning is important and will not only assure better looking water but longer life from your cartridge as well. A good pool filter cleaner will contain a combination of surfactants for oil and grease removal, as well as agents which will readily dissolve away built up minerals. It is recommended to have a spare backup cartridge because it will help extend cartridge life. This allows you to quickly exchange the cartridges when needed and to clean the dirty ones at a convenient time. Once cleaned, allow the cartridges to dry before reinstalling them. This allows the fibers to expand and fluff up thus providing more effective filter area. You will also find your cartridges will last longer before requiring replacement.
2. Diatomaceous Earth (DE) filters come in a variety of forms and are not as common as sand or cartridge filters. Typically they consist of a fine mesh fabric configured in a variety of shapes or forms including bags, grids or screens and “fingers”. DE is a fine white powder composed of the skeletal remains of microscopic organisms that lived millions of years ago. These skeletons are mined from the earth and cleaned. The powder is applied to the surface of the fabric and acts to trap dirt as the pool water passes through it. As the DE becomes clogged with dirt, it is washed off of the fabric and replaced with new DE to begin the process all over. DE provides excellent dirt trapping ability. The removal and recoating can be a chore and also leaves a disposal problem with the dirty material. As with other filters, the fabric on DE filters must be kept clean. If oils accumulate on the fabric the DE will not adhere properly and the resulting “holes”, areas with little or no DE in place, will allow water to pass through without good dirt removal. As with cartridge filters, regular cleaning with a quality pool filter cleaner, either the spray-on or the deep soak type, is needed in addition to the replacement of the DE when it becomes clogged.
3. Sand filters utilize sharp edged sand as the filtering medium. Sand grains are placed within a filter tank. Water flows down through the sand either under pressure or by vacuum. The dirt and debris becomes trapped within the grains of sand. The more dirt, the finer the filtration as this improves its ability to remove very small particles. Sand is regarded as a good filtering media because it does not react to most chemicals. In addition, the particles are irregular in shape so they tend to interlock which creates a fine filtering material. As sand filters become clogged with dirt, the filter begins to lose its ability to clean the water. This is most often indicated by a change in pressure on the pressure gauge or reductions in flow rate through the filter. When the flow rate through the filter becomes restricted due to the buildup of dirt and other matter in the sand, a process known as “backwashing” is used. Backwashing involves reversing the flow of water through the filter, which in turn causes the sand and dirt to “loosen”. As this process takes place, the loose-trapped dirt will be washed out from between the sand grains and flushed from the filter. Avoid unnecessary backwashing. Backwashing should only be performed when the pressure gauges indicate high pressure. This is typically no more often than once every week or two.

Backwashing:

To backwash a sand filter and in some cases a diatomaceous earth filter:

1.) Turn off pool circulation pump.

2.) Push handle on mpv. down and move to backwash position.

3.) Turn on pool circulation pump.

4.) Let pump run for about 1 minute or until waste water is clear.

5.) Turn pump off and turn to the filter to waste or rinse setting.

6.) Turn pump on and let it run approximately 15 seconds or until the waste water is clear.

7.) Turn off pump and turn mpv. handle back to the filter/vacuum to pool position.

8.) Turn pump back on.

 

The irregular shape of sand grains allows the grains to fit together tightly and thus help to trap fine particles of dirt. In time, the grains will lose their irregular shape and begin to form smooth surfaces, which do not filter as well. Often sand in this condition is considered old and in need of replacement. However, a good filter cleaner will actually remove the buildup of oils and grease and return the sand to a like-new condition. Sand filters should be cleaned once or twice per year in residential pools, and as often as every 3 months in commercial pools. Replace the sand every 5 years.

 

Circulation

Circulation is the movement of the pool water through the pump and filter system. In contrast, the term turnover refers to how long it takes for a given amount of water to pass through the pump. It is recommended for pools to have an eight hour turnover. This means that when the pump is running it will take eight hours for the net volume of water in the pool to move through the pump and filter system. It is important to note that turnover does not mean that all of the water in the pool went through the pump and filter. It could be the same water over and over, which is what happens when water is not properly circulating. The growth of black algae can be evidence of slow or “dead spots” in the pool that occur because poor circulation to those areas causes insufficient amounts of sanitizer or algaecide to reach those areas frequently enough to be effective. There are several things you can do to help assure proper circulation. Keep the bottom or main drain open so that a larger portion of the total pool water volume is being drawn through it. The skimmers then handle the rest. Adjust the return line fittings so that they direct the water flow in a generally circular pattern around the pool and also aim one or two gently downwards to improve water mixing from top to bottom. But also aim one or two upwards to ripple the water. This last point is critical in pools with no main drain or where the main drain no longer functions due to age, restrictive bylaws, or some other problem that is unable to be corrected.

Water outlets:

Water outlets are any pool opening where water goes out of the pool for circulation, some examples are:

a.) Skimmer: The skimmer is used to circulate water from the top of the pool and to “skim” debris off the water surface. It is critical that the skimmer be in good operating condition and functioning properly; the skimmer basket must be in place at all times and free from damage and the skimmer weir, (flap in the throat of the skimmer that maximizes skimming action), is in place and working freely. The skimmer is the place we recommend that you use to vacuum the pool to insure any large debris that may be vacuumed up is caught in the skimmer basket thus avoiding a potential plugged circulation line.

b.) Main Drain: The main drain is typically located at the deepest point of the pool and is used to lower the water level, however its primary purpose is to circulate water from the bottom of the pool. It is recommended that about 1/3rd of the circulated water come from the main drain. Some residential pools do not have main drains, instead relying on a deep water outlet to drain the pool and for extra circulation.

c.) Deep Water Outlet: A deep water outlet is located on the lower portion of the side wall and is used to circulate water and to lower the water level. A grate insert fitting must be installed to prevent suction entrapment.

d.) Vacuum Outlet: A vacuum outlet is installed on some pools and is intended to be used primarily as a suction port for vacuuming the pool. Extreme care must be taken when vacuuming a pool through the vacuum outlet so as not to vacuum up large debris that may become lodged in the circulation plumbing. We recommend you vacuum through the skimmer using a vacuum plate and skimmer basket if large debris is a concern.

e.) You may have other suction outlets designed into your pool for a unique purpose such as to feed a booster pump for a waterfall. The possibilities for this are endless and far to numerous to cover here. If you have any suspected water outlets beyond what we have discussed here consult with a reputable pool builder or service company for operating procedures.

 

Circulation Pump:

Your pool has a circulation pump that is responsible for moving pool water throughout the circulation system, (this is not to be confused with auxiliary pumps such as cleaner booster pumps, jet pumps, waterfall pumps, etc.). Water is drawn in from the pools outlets into the front of the pump, through the hair/lint trap, through the pumping chamber and out the top of the pool pump on its way to the filter.. Above ground pools and in rare cases inground pools have flooded suction pumps. These pumps need to be located below the pool water level because they are not capable of “pulling” a prime on their own and depend on gravity to keep them primed. The only maintenance for a circulating pump is to clean out the hair/lint trap basket as necessary and to lubricate the hair/lint trap lid gasket or o-ring with a non-petroleum based lubricant about once a month, (we recommend teflon or silicone based lubricants).

 

Determining what size pump is right for your pool: 5 Steps

 

1) Determine the number of gallons of water in your pool. The formulas for calculating the gallons depend on the shape of your pool.

For a RECTANGULAR POOL:

Measure the length (ft), the width (ft) and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in a rectangular pool is: Gallons = Length x Width x Average Depth x 7.5.

For example: your pool is 30 ft long and 15 ft wide. The pool's shallow end is 4 ft and its deep end is 8 ft. So, the pool's average depth is 4 plus 8 = 12 divided by 2. This gives you 6 ft. The pool's capacity is 30 ft x 15 ft x 6 ft x 7.5 = 20,250 gallons.

 

 For a ROUND SWIMMING POOL:

Measure the diameter of the pool (the widest line straight across the surface) and its average depth. The average depth is determined by adding the depth at the shallowest part to the depth at the deepest part and dividing by two.

The formula for calculating the total gallons in a round pool is: Gallons = Diameter x Diameter x Average Depth x 5.9.

For example (see picture): your pool is 25 ft in diameter, the pool's shallow end is 3 ft and its deep end is 7 ft. So the pool's average depth is 3 plus 7 = 10 divided by 2. This gives you 5 ft. The pool's capacity is 25 ft x 25 ft x 5 ft x 5.9 = 18,428 gallons.

For an OVAL SWIMMING POOL:

Measure the longest diameter, the shortest diameter and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in an oval pool is: Gallons = Longest diameter x Shortest diameter x Average depth x 6.7.

For example (see picture): Your pool's longest diameter is 25 ft, shortest diameter is 15 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is 25 x 15 x 5 x 6.7 = 12,563 gallons.

 

For a KIDNEY-SHAPED SWIMMING POOL:

Measure the largest width, the smallest width and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in a kidney-shaped pool is: Gallons = (Longest width + Shortest width) x Length x Average depth x 3.38.

For example (see picture): Your pool's length is 25 ft, longest width is 15 ft, shortest width is 10 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is (15 + 10) x 25 x 5 x 3.38 = 10,563 gallons.

 

2) Determine FLOW RATE (GPH), determine how many gallons per hour (GPH) you need to pump to clean all the water in your pool in eight hours. FLOW RATE =  divide your calculated gallons by eight. For the RECTANGULAR swimming pool example the GPH required is 20,250 gallons / 8 hours or 2531 GPH.

 

3) Calculate gallons per minute (GPM). To convert from GPH to gallons per minute (GPM), divide your GPH by 60 minutes (eg) 2531 GPH / 60 = 42.2 GPM. Having calculated your required GPM, you next have to figure out the average Feet of Head for your pool pump. Feet of head is the total of pipe length + valves and turns + filter and heater drag. For example:

Pipe lengths and rise = 28.0
Valves and turns = 4.7
Cartridge filter 70 sq. ft. = 7.5
Heater = 7.5

Total feet of head = 47.7

4) You now have the information required to select the size of your pool pump. Go to the description page of the style of pump you would like to purchase. Many pump manufacturers will provide a chart on this description page showing the HP required for your particular GPM and Foot of Head. For example, based on the data calculated above for a typical RECTANGULAR pool, we are looking for a pump that will handle 42GPM with a 47 Feet of Head. According to the typical chart for 50 Feet of Head (closest to 47'), we need a pump between 3/4 HP (31 GPM) and 1 HP (50 GPM). Since we always go for the higher GPM, we would select the 1 HP pump.

5) The size of your pool filter is directly related to the pool pump you have selected. If your pool filter is too small for the pump, there will be additional strain on the pump motor as it tries to push water through and encounters resistance at the filter. This will eventually burn out the pump motor and your filtration will also be compromised. We recommend selecting the filter so that it is oversized to be absolutely certain it can handle the flow coming from the pump. So, in this case, instead of getting a filter rated at exactly 42 GPM, you should select one that is a little higher – around 60 GPM would be fine.

There are a couple of other considerations that should be mentioned in your selection of a pool pump. The above calculations are based on a basic pool configuration with no extra water features like: fountains, spas, waterfalls, solar heating, and in-floor cleaning systems. These features generally require higher GPM rates which equate to a higher HP pump.

 

Heater:

The typical pool heater is fueled by either natural or propane gas. Electric is an option but is costly and better suited for portable hot tubs. The pool water passes through the heat exchanger which is located in the fire box above the flame bed, thereby collecting heat from combustion and transferring it into the pool water. Pool heaters are lit either by electronic ignition or a pilot light and are controlled by a thermostat. A pool heater thermostat operates similar to an oven; you set the thermostat to the desired temperature and the heater turns on all the way and continues running until the desired temperature is reached, and then turns off, (note: a pool heater will only operate when the pool circulating pump is turned on). There is no routine maintenance for a pool heater other than to be sure no combustible material is on top of or leaning against the heater. Refer to the owners manual or contact a reputable service company for operating instructions and other safety precautions. The pool water then goes back to the pool via the returns.

 

Returns:

Pool water returns are places in the pool where water comes back in from the circulation system. A typical pool has two or three returns depending on the pool size. The return is usually a 1 1/2″ threaded opening that may have a directional eyeball that screws into it, (directional eyeballs are used to “aim” the water thereby enhancing proper water circulation within the pool).

 

Chemical Feeders:

Your pool may have an automatic chlorinator/brominator attached to the circulation system. Pool water is directed through the feeder where sanitizer is eroded (slowly disintegrates) into the pool water and sent back to the pool. The feeder should have a metering valve that adjusts the rate sanitizer is added to the pool. The only maintenance is to lubricate any cover o-rings with a non-petroleum based lubricant and add chlorine/bromine tablets as necessary.

 

Mineral Purifiers:

Your pool may have a mineral purifier, (Nature 2, Vision, Frog, etc.), that is plumbed in line within the circulation plumbing. Inside the purifier vessel is the cartridge that contains the purifying minerals; the cartridge must be replaced every 4-6 months. There is no maintenance with these units as the minerals sort of maintain themselves, however, there is a start-up procedure for new cartridges that must be followed using the manufacturers directions.

 

Cleaner Booster Pumps:

You may have an automatic pool cleaner that uses a booster pump to power the cleaner, the most common brand is Polaris. The pump draws water from the pool circulation plumbing and pushes it back to the pool via the dedicated cleaner line to which the automatic cleaner is connected. There is virtually no maintenance with this pump however it must not be turned on unless the pool circulation pump is running; the booster pump is not self priming and depends on the circulation pump to prime it and keep it primed.

 

Ozonators:

Some pools have an ozonator which adds ozone to the pool water somewhere in the circulation plumbing. Ozone acts to destroy organic waste and break down chloramines and bromamines. Some ozonators have a metering valve to control the air flow or ozone production. Follow the manufacturers directions for setting the flow rate. The ozone generation cell will eventually burn out and require replacement.

 

Non mechanical considerations

Flocculants, enzymes, and oxidizers

Even though the filter is working properly and the circulation pattern is correct, the pool water can still appear hazy or dull, due to microparticles that are so small that they simply pass through the filter media without being trapped. Add a water clarifier, or enzyme solution to solve this problem. A water clarifier will clump particles together and are easily filtered out. Used regularly, a clarifier will reduce maintenance, improve filter performance and enhance the appearance of the pool water. In severely cloudy water, (spring opening), the use of a flocculant.

Flocculant

A flocculant coagulates the cloudy water particles into masses that settle quickly to the pool floor so that they can be vacuumed up easily.

Flocculants enhance, and are often required to make possible solid-liquid separations from turbid to high percent solids in water.  Typically, solid particle sizes in water have a wide normal distribution and are inorganic and organic based.   If these particles are denser than water, the particles will settle to the bottom of a container if given sufficient time; however, many of the smaller, lighter particles remain suspended (think a cloudy mud puddle that appears to swirl with activity) for a much longer time than allowed with a typical residence time.  That is because the particles, or colloids, are small enough to remain suspended by external forces including Brownian motion (interaction with the water molecules), thermal currents, dispersive surface charges and the like.  These are the hardest particles to treat because they are so fine and do not easily and quickly settle.

 

Unless the particles are uniformly coarse (depending on the water chemistry conditions and relative solid and water densities, coarse particles might be considered greater than 100 mesh or greater than 210 microns) and rapidly settle by gravity, flocculants are required to aggregate multiple particles together as ‘floccules’ which are pseudo-large particles.  Enter the flocculants!

Polymers are ubiquitous materials ranging from nylon, polyethylene plastics, Teflon, and starches to amino acids.  Flocculants belong to the water soluble polymer class, and so they fully dissolve in water.  These are acrylamide based with functionality groups which allow the polymers to readily chemically adsorb to particles.  These polymers are very long (for perspective, if you expanded a flocculant molecule to 1 inch in diameter, the total length would be on the order of 1.25 miles long!)  As flocculant molecules dissolve in water, these molecular chains (ropes) are free to uncoil and expand, but are never completely linear due to random Brownian motion and water thermal current effects.

In effect, these flocculant ropes lasso aggregates of particles together.  Since the polymer chains are very long, these polymers agglomerate multiple colloidal and coarse particles together.  As these flocculated aggregates continue to mix, the polymer rope continues pulling the particle aggregate into a tighter and denser floccule, which causes the particles to settle more readily. The larger floccules are more easily filtered, centrifuged and floated in a dissolved air flotation unit.

The initial step of ‘coagulation’ is where a short cationic (positive) charged polymer coagulant is added to partially neutralize the repulsive particle’s negative charges and induces pin flocc aggregation of the colloidal particles.  Then the flocculant molecules ‘lasso’ and flocculate these pin floccs into larger floccules.

 

Enzymes and Oxidizers

Accumulations of body oils, cosmetics and other complex bather waste can result in the buildup of these materials along the waterline and in pipes and filters. This waste can cause unattractive scum lines and interfere with the performance of the sanitizer, a problem that will affect the overall appearance of the water. We recommend the use of enzyme digestive products to control bather waste in the water, and to prevent their buildup on the walls and in equipment. Enzymes help in the breakdown and removal of stains and deeply-set soil.

Enzymes are made up of proteins and amino acids, and they catalyze certain chemical reactions. Our bodies contain countless types of enzymes that help us process food and other things. Pool enzymes are made to break down and digest non-living organics, which makes water cleaner, and chemicals more efficient.

Enzymes are naturally occurring biological catalysts. They help increase the breakdown rate of complex compounds. In pools, specially developed natural based enzymes are used to help break down complex materials like oils and grease. With regular use they will take these very complex and difficult to control materials and break them down into smaller fragments that can be easily destroyed by shock oxidation treatment.

Enzymes work by attracting (or seeking out) a given type of molecule, known as a substrate. The enzyme has a special place that fits that type of substrate and nothing else, and either binds two substrates together, or breaks one apart. Swimming pool enzymes break the non-living organic molecule apart, and digest the carbon bonds, and convert them into CO2. This CO2 then off-gasses as small clusters of bubbles on the pool surface, which is noticeable for several hours after the initial enzyme treatment, called the purge dose.

Chlorine is the primary sanitizer in pools. Killing germs and keeping the pool safe to swim in is the primary purpose of having a residual sanitizer in the first place. Oxidation is chlorine's secondary responsibility, yet the vast majority of contaminants in water are non-living oxidants. That is why  enzymes help chlorine work better by eliminating bather waste.

Chlorine and bromine are primary sanitizers and oxidizers for swimming pools. Oxidation is a chemical process where electrons are stolen from an oxidant (like bather waste or metals). In swimming pools, oxidation is basically burning contamination out of the water, but at the expense of chlorine, because along with oxidation comes reduction. Eventually that oxidizer has no more ability to steal electrons, and can therefore no longer oxidize. By the term “chlorine is "used up", we mean it was reduced. Without enzymes, oxidation is virtually the only way for a swimming pool has to rid itself of non-living organics and oils. And while chlorine is an excellent sanitizer, it is a relatively lousy oxidizer.

Downsides of Oxidation

While there are some oxidants that enzymes cannot address–like ammonia and other nitrogen compounds–the vast majority of oxidants in a swimming pool are carbon-based. In other words, non-living organics. These include bather waste like sweat, body oils, saliva and mucous, as well as bather products like lotions, cosmetics, sunscreen and anti-perspirant. The downside is that oxidation reduces chlorine.

Chlorine oxidation is not as effective as enzymes against bather waste. That is why so many pools that rely on chlorine have problems like scum lines and oily water and often struggle with cloudy water. That is why sand filters routinely get fouled with organic grease and grime. These problems often cease to exist when a pool is being treated with enzymes (such as Orenda).

Not all enzymes are well suited to pool use. Many enzyme products are better suited for spas and hot tubs. Enzymes are manufactured by living organisms and since chlorine and other sanitizers destroy living substances, it is important to select enzymes that can tolerate the typical sanitizer levels commonly found in pools and spas. Use enzymes that have been properly selected for digestion of the types of oils and greases found in pool water. In spas, the enzyme will help reduce the buildup of organic wastes on filter media and thus reduce the frequency of cleaning as well as improving water appearance.

 

1. Chemical and mineral elements

Proper chemical and mineral treatment of water is important to prevent problems such as:

scale and stain formation,

colored or cloudy water,

corrosion of pool surfaces and equipment and to assure

proper performance of the sanitizer being used.

 

The five chemical factors that affect water quality are:

         pH                                                           7.2-7.8                                   water balance

        Total Alkalinity                                     80-120 ppm                           water balance

        Calcium Hardness                                100-400 ppm                        water balance

        Stain Producing Minerals

        Total Dissolved Solids (TDS)               250-1500 ppm

 

pH , power of Hydrogen

pH refers to the degree of activity of an acid or base in the water. It is measured on a scale from 0 to 14 with 7 being neutral. A pH value between 0 and 7 is considered acidic with 0 being the greatest acid activity and getting weaker as it approaches a value of 7. A value of 7 to 14 is considered basic with 14 being the greatest base activity. Ideal pool water pH is in the range of 7.2 to 7.8.

When pH lingers below 7.0, the water is considered to be corrosive. This means etching of plaster and metals in equipment such as heat exchangers may result. It is more difficult to keep (stabilize) chlorine in the pool because while more effective as a sanitizer at the low pH, chlorine is also much less stable resulting in the consumption of larger quantities of chlorine than would be used at normal pH levels.

On the other hand, maintaining the pH higher than 7.8 will increase the tendency to form scale or cloudy water. Calcium, the major component in scale, is a relatively unstable mineral and when the pH is high, the calcium is not as soluble and it will tend to precipitate or “fall out” of solution resulting in cloudiness or scale. High pH will also reduce chlorine effectiveness resulting in the need to maintain higher chlorine levels to achieve maximum sanitization.

To increase low pH,  sodium carbonate,  pH UP or soda ash, is added to raise the pH. To decrease pH add pH DOWN or liquid acid (muriatic acid) or dry acid (sodium bisulfate).

The most frequent  cause of change in the pH of pool water is the sanitizer used. Of the sanitizers typically used in pools, chlorine is the most common. Chlorine comes in a variety of forms and varies widely in pH.  For example, stabilized forms of chlorine have a very low pH and will tend to lower pH over time, while liquid chlorine is very high in pH and will tend to raise pH values. Changes in pH due to sanitizers or other factors can be minimized by controlling alkalinity.

 

Total Alkalinity

Total alkalinity will neutralize substances that try to effect pH and stability of the water and helps keep the pH in the desired range. Total alkalinity does not determine what the pH will be, but rather acts to help keep the pH in the 7.2 to 7.8 range. Total alkalinity is measured in parts per million (ppm) using a total alkalinity tester with a target range of 80-120 ppm.

To adjust total alkalinity downward, the same acids used to lower pH are employed. When reducing total alkalinity, it is best to add small amounts of acid, either liquid or dry, over a period of several days as opposed to making large adjustments rapidly. Each time the acid is added the pH will drop initially and then the total alkalinity will neutralize it. This results in the pH returning to the previous level and the total alkalinity value will drop. Simply repeat the process daily until the desired level is reached. Adding too much acid at once may result in lowering the pH so severely that corrosion of pool surfaces and equipment may result and the existing total alkalinity may not be sufficient to raise the pH back to the normal level.

When raising total alkalinity, sodium bicarbonate is the chemical of choice and the required amount can be added all at once. If total alkalinity and pH need to be adjusted, it is recommended that you adjust the total alkalinity before the pH. Never add acid to the pool water if the pH is less than 7.2, even if the total alkalinity is high, wait for the pH to rise naturally.

 

Calcium Hardness

Dissolved calcium is invisible unless the pH rises higher than 8.0. The calcium dissolved in water is called calcium hardness. Soft water refers to water with lesser or no levels of calcium. (Think of your water softener at home). Calcium becomes unstable at very high levels and become even more unstable if the pH or the total alkalinity rise above the normal levels. These imbalances can result in cloudy water and/or scale.

As water temperature rises, calcium becomes more likely to precipitate out of solution. Calcium is actually more soluble in cold water. (Think of the white calcium deposits inside of a tea kettle).

Too soft water is aggressive and will actually remove calcium from plaster in concrete pools in order to satisfy its need for the mineral. If the pool is vinyl or fiberglass, the low calcium water will attack metal fittings and heat exchangers resulting in destruction of the fittings or pinhole leaks in the heater. Salt water pools, with too soft water, are often subject to corrosion.  When such corrosion occurs, it is also common for stains to appear on pool surfaces. These stains are mistakenly blamed on metals in the water such as iron or copper when, in fact, it was the hardness of the water. 

Calcium content is best in the range of 100-400 ppm, but higher levels can be tolerated when properly managed. The safest and most reliable way to reduce the calcium of your pool is to remove and add fresh water back into your pool.  If you have a pool pump and filter that has a backwash option, you can use the occasional backwashing you have to to anyway as an opportunity to remove a little extra pool water and refill the pool with fresh water. (Otherwise set your filter to “waste”). Here are a few general instructions on backwashing and refilling your pool:

1. First test your pool calcium hardness level.  You need to first know how your current calcium hardness level.
2. Determine how much water you need to remove from your pool.  If you are over the ideal calcium hardness range (400 ppm), you may need to drain about one-fourth of your pool to bring the level down.  This can be an expensive undertaking if your local water rates are high, so you should talk to a local pool service provider first to see what is typically done in your area.  They have experience with this and can give a rough estimation of how much water to drain to avoid unnecessary draining, but make sure you drain enough to affect the calcium hardness level.
3. Drain a portion of your swimming pool water, either by backwashing or siphoning the water.  You can siphon water out of your pool if your pool is above ground or the ground behind the pool slopes enough away.  Be sure to turn off your pool pump if you siphon the water and expect the pool water level to go below the pump water inlet.  You do not want the pump motor to be running without any water flowing through it.
4. Refill the water you have drained.  Wait at least six hours for the fresh and existing water to mix together, as the cold source water might have sunk to the bottom of the pool if your existing pool water is warm.
5. Retest your pool water for calcium hardness and determine if you are within the ideal range, or if you need to lower the calcium hardness level again.

Another, or additional way to reduce calcium levels is adding flocculants, that can help attract minerals that have gone out of solution, where your water is very hard. Calcium that is dissolved in the water, or in-solution, likely will not be affected by the flocculant.  Flocs  really only cause solids already out-of-solution to stick together, so that they can be vacuumed or filtered out of the pool water.  In this case, you may can:

1. Use a flocculant to rid the pool of free-floating calcium carbonate.
2. Vacuum the walls and floors of the pool, so the excess calcium carbonate particles are pulled into the pool filter.
3. Backwash or clean out your pump filter.
4. Drain a portion of your pool water and refill with fresh water.
5. Test the pool water for calcium hardness.  With the excess calcium carbonate removed and fresh water added, you can should notice a reduced calcium hardness level.

Finally, in cases where  it may be difficult to reduce calcium hardness, it is possible to control it so that a potential problem such as cloudy water or scale formation is prevented. The best way to minimize the effect of high calcium levels is through the use of a sequestering agent. A sequestering agent is a compound that, when added to water, will chemically bond with calcium and other minerals such as magnesium,  to make them, (in a sense), more soluble. This means that calcium will still be present, but in a form that is less likely to cloud water or form scale if the pH or other factors get out of balance. In addition, since calcium will still be in the water, you will not have the corrosion problems you would otherwise experience with soft water. A further advantage is that elevated levels of calcium (over 400 ppm) can be tolerated without constant need for dilution. This becomes especially important when the pool is located in hard water areas or calcium-based chlorine sources are used.

 

Mineral Staining

The use of sequestering agents becomes even more important in the control of stain producing minerals. Problems of stain formation on pool surfaces or colored water are most often associated with the metals iron, copper or manganese. Each of these metals can enter a pool by several means and will react in very different ways. One of the most common ways these metals can enter the pool is via the fill water. Therefore, before filling a pool, always be certain to have the water tested for all three metals in addition to the other chemical parameters. In this way you will be better prepared to deal with the initial pool treatment, both water balance and stain control.

IRON

Iron is the most common mineral found dissolved in water. It is colorless but will react almost instantly with chlorine or other oxidizers to produce a rusty red color in water, or worse, orange colored staining. As little as 0.1 ppm of iron is all that is needed to result in colored water and stains. The most common source of iron in pool water is the fill water. However, a simple water test does not always alert you to the possible presence of iron in the fill water. This is because over time, municipal drinking water piping systems gradually build up sediments in the pipes. This is not normally of great concern as the water flow is generally not sufficiently strong enough or of high enough volume to stir up these sediments into the flow of water itself. Often times when large quantities of water are drawn from municipal pipes, such as when a pool is first being filled, the heavy flow of water can cause ironbearing sediments laying in the pipes to be stirred up, causing them to enter your pool unexpectedly. If a test for the presence of iron were conducted prior to filling the pool, it would only identify iron if it were naturally occurring in the water. Any iron that may be in the sediments would likely be missed because the small amount of water drawn for the water sample would not be sufficient to stir up the sediments. Thus, the iron would remain in the pipes and not be detected until it was too late. The result could be a heavily stained pool that would then need to be emptied, cleaned or acid washed and refilled.

COPPER

 A common cause of green water and stains ranging in color from blue-green to black is copper. Copper sources are more varied than iron. Copper can enter the pool water from corrosion in copper heaters, from some copper-based algaecides, and from the source water. Copper problems are often indicated by pool water with a true clear green color, whereas green water caused by algae would be green and cloudy.

Corrosion of gas or oil-fueled heaters that have copper coils results in copper entering the water flow, which, in turn, can lead to green water or stains. This type of corrosion is most commonly due to a chemical imbalance in the water such as low pH, low total alkalinity or low calcium hardness or a combination of these factors. A galvanic action can take place in heaters where the copper metal of the heater coil comes in contact with a different metal such as iron.

Copper algaecides are also implicated in causing stains in pools because of how the product was applied to the pool in the first place. Copper algaecides come in several types and some are more prone to staining than others. However, copper algaecides are usually very concentrated, requiring only a very few ounces to be applied for each 10,000 gallons of pool water. Often times, label directions are not followed and a significant overdose occurs. That is why it is important to follow the label directions. Copper can also come from the source water and will either be present as a normal component of the water or on a periodic basis. Many municipal water systems rely upon reservoirs for their water supply. These reservoirs frequently suffer from algae outbreaks and the algae is treated with copper. The copper level is often as much as 1.0 ppm, and if you fill or add water to your pool with this water, it will be green and could result in staining.

MANGANESE

Manganese will color the water from pink to deep purple depending on the level present. Manganese only enters the pool from the source water either through natural occurrence or after being intentionally added by a water treatment plant in the form of potassium permanganate ( as a iron removal chemical). The latter causes problems when it is inadvertently overdosed and then arrives at the pool when filling or adding water. Again, the biggest problem is that you simply do not know when the water may contain manganese. The important thing to understand is that all three metals can easily be kept from causing problems with the regular use of a sequestering agent.

As with calcium, the sequestering agent will chemically combine with the metals in the water and keep them from precipitating out of the water to cause staining. The best time to use a sequestering agent is when the pool is being filled for the first time, and thereafter as part of a regular preventive maintenance program. In this way, any metals that may be present in the fill water will be tied up or inactivated before they can cause a problem. Also, any metals that may find their way into the pool, either when water is added or from corrosive actions in the pool, will be prevented from causing staining. In other words, by adding the sequestering agent as part of the regular maintenance program, the pool will be protected from stains even when you did not expect metals to be present. It is far easier to prevent staining caused by metals than to remove the stains once they have formed.

TOTAL DISSOLVED SOLIDS

 Total dissolved solids (TDS) are normally the least worrisome factor.TDS is the sum of all materials dissolved in the water and normally runs in the range of 250 ppm and higher. There is much discussion over what levels are considered too high, but there is no real lower limit. TDS is comprised of many different chemical compounds, which means that the issue of how much is too much actually depends more on what they consist of than how much there is. For example, sodium chloride or ordinary salt is extremely soluble and is therefore unlikely to cause a problem, whereas, as we have seen, calcium compounds can be a problem even at fairly low levels. In general, when the TDS exceeds approximately 1500 ppm, problems may begin to occur. It must be pointed out that pools whose sanitizing systems are based on chlorine or bromine generation equipment (salt generators) will likely have much higher TDS levels. These pools actually have salt in one form or another added to the pool. The salt used is highly soluble and does not cause the type of problems normally associated with high TDS, but never the less, it does add to the TDS level in the pool. When testing water in this type of pool for TDS, the salt intentionally added to the pool needs be taken into account. At elevated levels,TDS can lead to cloudy or hazy water, difficulty in maintaining water balance, reduction in sanitizer activity and foaming. Unfortunately, the only way to reduce TDS is to drain a portion of the water and replace it with fresh water. Sequestering agents do not help when high TDS levels are causing cloudy water.

1. Sanitization and Algae Control

 

SANITIZATION

The process of controlling bacteria in the water is known as sanitization. Sanitizaion is not to be confused with the control of algae in the pool water, as algaecides are best used for that purpose. While a wide variety of methods for sanitizing pools are available, the two most common methods are chlorineand bromine. Other processes have also gained more attention, including PHMB (biguanide), ozone and ionizers. Each has its strengths and weaknesses.

 

CHLORINE

Chlorine is the most widely used anti-microbial for pools. The following table lists the most commonly used forms of chlorine and some of their characteristics:

CHLORINE                               PRODUCT FORM                               CONTENT                             pH

Sodium Hypochlorite    liquid bleach, liquid chlorine              Liquid 10-12%                       13-14

 Dichlor                            granular stabilized chlorine              Granular 56-62%                       6-7

Trichlor                           tableted stabilized chlorine          Tablets, Pucks & Sticks 90%         2-3

Calcium Hypochlorite    granular chlorine, unstabilized         Granular 47-75%                  11-13

Free Chlorine  is the most desirable form and is the form responsible for the actual sanitization activity in the water. It is measured using a free chlorine test kit and its level is critical in the pool. If this form is not present, little or no sanitizing can take place. Free chlorine is composed of two types of compounds: HOCl (hypochlorous acid) and OCl¯ (hypochlorite ion). They exist together in equilibrium. This means that together they make up 100% of the free chlorine content, but that content consists of some of each. For example, if 25% of the free chlorine is HOCl, then the OCl¯ level will be the other 75%. It is important to note that only the HOCl component is effective as a sanitizer. Therefore, it seems logical that we would want as much of the free chlorine as possible made up of the HOCl. However, the level of HOCl and OCl¯ present is dependent upon the pH. This is one of the critical reasons that the proper pH level in pool water is so important.

As the pH goes up or down, the relative amount of HOCl vs. OCl¯ also increases or decreases. The following chart shows how much of each of these two compounds are present at different pH levels.

                            pH                                                         %HOCl                             % of OCI¯

                           6.0                                                             97                                        3

                           7.0                                                             75                                       25            

                           7.5                                                             50                                       50

                          8.0                                                             23                                        77

                          9.0                                                               3                                        97

As the chart shows, at pH 7.5 only about half of the free chlorine exists in the desirable form of HOCl. The level of HOCl will increase as the pH goes down and it must also be pointed out that as the pH decreases, so does the stability of the chlorine. As pH rises, the stability of the free chlorine will increase, but its activity as a sanitizer diminishes. In order to get the most effective and economic benefit of chlorine, keep it in the desirable pH range of 7.2-7.8. Lower pH will be detrimental to pool surfaces and equipment, while higher levels will render chlorine ineffective as a sanitizer.

Combined Chlorine

 Free chlorine is highly reactive and once added to water, quickly attacks bacteria as well as bather and other wastes. When this occurs, the chlorine is no longer considered free chlorine but rather its form has changed and is now referred to as combined chlorine. Bather and other wastes are largely made up of ammonia and nitrogen compounds. (These gasses are sometimes misunderstood to be too much chlorine). Combined chlorine is very stable, but has little or no sanitizing ability. Not only is combined chlorine a very poor sanitizer, it is the agent responsible for eye burn and skin irritation and results in the unpleasant chlorine odor often referred to as a pool with “too much chlorine”. It is therefore critical for bather health and comfort that combined chlorine be controlled and kept to a minimum. It is preferable that combined chlorine levels are kept to a maximum of 0.2 ppm.

 

Total Chlorine

Free chlorine + Combined chlorine = Total chlorine.

Total Chlorine – Free Chlorine = Combined Chlorine.

 

BROMINE

Chlorine and bromine are both members of the same chemical family known as halogens. While not as popular as chlorine, bromine has gained wide acceptance as a sanitizer, especially in hot tubs where the hot turbulent water tends to increase the amount of wastes in the water. The heavy waste accumulates and then places a stress on chlorine resulting in odors and irritation due to the buildup of combined chlorine. Bromine does not suffer from this problem. Bromine is available in three basic forms: tablets, sticks and caplets or as a two product system. When added to water, bromine forms hypobromous acid (HOBr) similar to the hypochlorous acid formed by chlorine. However, unlike chlorine, the amount of hypobromous acid is less dependent on pH. Additionally, the combined bromine that forms when the HOBr combines with wastes in the water does not diminish bromine effectiveness like it would with chlorine. A further advantage is found in the resulting compounds, known as bromamines, which do not cause eye and skin irritation or foul odors. For this reason, it is not necessary to test for both free and combined bromine. Only a test for total bromine is needed. Bromine tablets, sticks or caplets are usually applied through some type of feeder device either in-line or, in some cases, as a floater-type feeder. The two-product system relies upon the addition of small amounts of an inert sodium bromide salt, which by itself does little. The water is then treated with an oxidizer specially suited for this purpose, or with chlorine. The oxidizer or chlorine acts to convert the sodium bromide into free bromine. When chlorine is used this way, it reacts only to make bromine and does not act as a sanitizer itself.

BIGUANIDE (PHMB)

Another sanitizer for pools is biguanide, or PHMB. This compound has come to be known as a “non-chlorine” sanitizer, but perhaps would be more accurately called “non-halogen” since it does not rely on either bromine or chlorine. The PHMB system has created interest because it is said to be free of chlorine odors and irritation. Many people like the idea of getting away from the use of traditional sanitizers. While PHMB can be effective in controlling most microorganisms, the system is different from traditional sanitizers and has some drawbacks. For example, the system does not tolerate the addition of chlorine or bromine, and if added to a biguanide pool, these products can cause the formation of gummy deposits on surfaces and pipes. Since most source water contains chlorine as a treatment chemical, small amounts of the gummy deposits can form over time. On the positive side, the product is stable in the water and needs to be added only in top off doses every week or two and does not require the constant testing of levels as do chlorine or bromine. Absence of chlorine odors, reduced skin irritation and ease of maintenance are also claimed.

OZONE

While ozone has gained wide acceptance and use in hot tubs, it is now gaining more use in pools as well. Chemically, ozone is a highly reactive oxidizer and is the most effective of all oxidizers in its ability to kill the microorganisms it comes in contact with. Because it is so reactive, it must be produced on-site by specialized equipment or UV light. In nature, ozone is produced by electrical discharge such as occurs in lightning. While effective, ozone is not very stable because it has a very short life in the water, which means that only water and contaminants actually in contact with ozone at any given moment can be considered sanitary. Therefore, ozone must be supported by the use of a backup sanitizer – usually chlorine or bromine. The advantage ozone holds is that it will reduce the levels of chlorine or bromine normally needed to operate a given pool.

 

 

MINERAL TREATMENTS

Minerals such as silver and copper have long been recognized for their ability to keep water fresh for drinking. The pioneers used to place copper and silver coins in their barrels of drinking water as they traveled west. Over the past 50 years or so these minerals have been used to treat pool water. The minerals copper and silver have received most of the attention and more recently zinc has gained interest as well.

Using copper sulphate algaecides

Copper sulphate-based swimming pool algaecides can be used to:

• control algae
• improve water clarity
• reduce the amount of chlorine- or bromine-based products needed

They do not:

• control microorganisms like bacteria and viruses
• eliminate the need for sanitizers

Copper sulphate-based products must be used along with chlorine- or bromine-based sanitizers to protect bathers.

The amount of copper sulphate-based algaecide needed will vary depending on the size and type of your pool and its location, for example how much sunlight it receives.

Note: Using copper sulphate-based algaecides in swimming pools is not dangerous to swimmers. Also, these products are not known to cause corrosion of pool equipment. If you follow all label directions, copper sulphate algaecides should not cause skin irritation. However when handling undiluted products, care must be taken to reduce the risk of skin irritation.

The levels added to water do not assure control of all bacteria or algae and it is highly desirable to supplement these minerals with low levels of chlorine or bromine. The combination of the halogens and minerals results in a true synergistic ability to control undesirable organisms and wastes at low levels.

 

SHOCK/OXIDATION TREATMENT

Control of bather and other wastes is important for comfortable swimming. Wastes can build up and eventually corrupt the water. The best way to remove these wastes is with regular oxidation. The odor that is associated with combined chlorine is often mistakenly referred to as “too much chlorine in the water,” but actually indicates that there is too little. Shock oxidation treatment or super chlorination is needed to destroy these wastes. The term shocking means to add enough chlorine to pool or spa water to destroy all combined chlorine present in the water.

We use the phrase “shock oxidation treatment” when referring to the use of non-chlorine type shock-oxidizer. Conversely, the phrase “super chlorination” is used when referring to the use of a sudden large dose of chlorine. In either case, the goal is to destroy and remove bather waste in addition to preventing the formation of combined chlorine or the accumulation of irritating waste products.

SUPER CHLORINATION

Superchlorination produces free chlorine that reacts with organic contaminants to form a variety of disinfection byproducts (DBPs) which are hazardous to swimmer health e.g. one of the worst DBPs is the noxious and volatile trichloramine (NCl3), well known for irritating the eyes nearby a pool. It has been pointed out that ozone is an excellent alternative, a much more effective oxidizer than chlorine shock.

Super chlorination is effective in eliminating wastes or destroying combined chlorine. To achieve successful super chlorination, a single large dose of chlorine is applied to the water. Super chlorination actually works by first reacting with the organic wastes in the water to form more combined chlorine. Once a sufficient level of chlorine has been added, all of the organics will have been reacted with (oxidized), and only then will the combined chlorine break down leaving free chlorine. Typically, the amount of chlorine required is ten times the level of combined chlorine in the water. For example, if the chlorine test shows a level of 1.2 ppm of combined chlorine you will need to add 12 ppm of additional chlorine in order to destroy all of the combined chlorine. Chlorination also has a number of drawbacks, which include:

• requires a large amount of chlorine
• can damage liners and swimsuits
• upsets water balance
• difficult to determine proper dosage
• cannot swim until free chlorine level drops to 1-4 ppm

When using chlorine to destroy combined chlorine, failure to use a sufficient quantity will actually result in more combined chlorine, odor and irritation rather than less. The use of too much chlorine can cause the types of problems listed above.

SHOCK OXIDATION TREATMENT

Shock oxidation treatment is a phrase commonly used when referring to the use of a product that does not contain chlorine to eliminate wastes in the water. Instead, it uses a unique oxidizer to control wastes. (Must be compatible to your enzyme product or as a substitute for an enzyme). Most commonly referred to as “non-chlorine” shock, oxidizer it does not use chlorine to destroy the wastes, as the name implies. Non-chlorine shock uses an oxidizer that will directly oxidize the waste itself, whereas chlorine used in super chlorination works by first changing the waste into combined chlorine before final breakdown. Since non-chlorine shock oxidizer does not require chlorine, it can be used to destroy waste products before they have a chance to form combined chlorine, and it offers several significant advantages including:

• does not require excessive chlorine use
• will not harm liners or suits
• will not upset water balance
• easy to determine needed dosages
• can swim as soon as 15 minutes after treatment

Shock oxidation treatment or super chlorination should be administered at the start of the pool season. Frequency of application thereafter depends on several factors including: bather load, heavy rains or the presence of combined chlorine. Most residential pools should be shocked every week or two, while commercial pools should be treated at least weekly and more often if there is a heavy bather load or if the combined chlorine level is greater than 0.2 ppm.

Heavy rainfall also places a large amount of debris or organic material into pool water that can lead to combined chlorine or even algae growth. Shock oxidation treatment following a heavy rain will help in avoiding these problems. The best way to handle problems, including combined chlorine, is to prevent them from occurring. Non-chlorine shock oxidizers prevent the problem before it occurs. Super chlorination is most often used after the problems with combined chlorine become obvious.

 

ALGAE CONTROL

There are two basic groups of algae:

1. The free-floating types include the green and mustard varieties. They tend to be found throughout the water. While they may cling or settle on surfaces such as walls and floors, they are not usually affixed to them and are easily brushed off. They tend to color a water body cloudy green or yellow.

2. Black algae is the common name or term given to the dark blue-green algae found growing on pool surfaces. Black algae growth in localized areas such as along one wall, in the deep end, in a corner or around obstacles such as steps indicates an area of poor circulation.

 

The most common cause of irritation for pool owners is water that is green and cloudy. It is the most obvious sign of something gone wrong in pool maintenance. Proper maintenance will not only keep your water looking great, but also allow for easy prevention of algae growth.

The growth of both types of algae can be easily prevented by using a quality algaecide as part of a regular maintenance program, and by proper circulation and filtration. It takes far less algaecide to prevent algae growth from getting started than it will to cure it once it has occurred. The regular use of algaecide is also recommended to prevent problems, should a failure of the sanitization program occur. Due to the volatile nature of chlorine or bromine, these residuals can often be lost very quickly in pools due to equipment or operator error or by heavy rainfall or bather waste demand. If this occurs without an algaecide present, the rapid growth of algae can occur in a few hours. However, if an algaecide is present, it will act as algae growth prevention until the sanitizer system is functioning normally.

In spite of our best efforts, algae problems do occur and require some consideration for proper treatment. When an algaecide becomes necessary, the following factors need to be considered before treatment:

• The number of algae present. It is critical that sufficient algaecide is added to treat all of the algae at one time. The use of only some of the needed algaecide will not kill some of the algae. Ideally, have an active algaecide present that only needs to be topped up every week or so. It is important to follow the directions for use on the package.
• Age of the algae. The older algae becomes, the more difficult it is to control. Treat the problem as soon as it is noticed.
• Sunlight and water temperature. It is best to treat when algae are actively growing. Sunny days and a water temperature of 60ºF or higher will be helpful.
• Type of algae. Different types of algae require different types of treatment.

GREEN ALGAE

The most common algae associated with swimming pools is green algae. It is very opportunistic, meaning it will take advantage of any failure in the normal sanitizing program and quickly infest a pool. One will see green algae problems frequently appear overnight following heavy rainstorms. This is because rainstorms, especially those with lightning, actually provide food for the algae in the form of nitrogen. The nitrogen not only feeds the algae but also destroys chlorine residuals by forming combined chlorine. Green algae must not be mistaken for problems with copper content in the water. If high levels of copper are present, the water will become a clear green, whereas green algae will cause a cloudy green appearance. The best way to treat for green algae is to prevent it in the first place. Use an algaecide regularly as part of a normal maintenance program. This will prevent algae from growing, even if a failure in the sanitizing system was to occur. It is always easier and more effective to prevent the algae problem than to try and eliminate it once it occurs. When it does occur, treat it promptly. The longer the wait before treatment, the more difficult and costly the result. Select an algaecide that will both treat the existing algae and prevent renewed growth. Follow the label directions and maintain circulation during treatment.

YELLOW OR MUSTARD ALGAE

The yellow or mustard algae is very similar in form to the green algae, but is much slower growing and is deficient in chlorophyll (green pigment) which accounts for its yellow color. Because yellow algae grow very slowly, it is also very difficult to destroy. By the time you see it growing in your pool, it has likely been there as long as several weeks. Additionally, since yellow algae is low in chlorophyll which is light-loving, the algae live and even grow in dark areas of the pool such as plumbing and filters. This only compounds the difficulty of control. Care in selection of a proper algaecide is most important. Be certain to select a product made for the control of this unique form of algae. Copper-based algaecides seem particularly well suited for controlling yellow algae, but others, including recently developed synergistically blended products, are also effective. One word of caution: it is not unusual to need to treat yellow algae more than once to bring it fully under control. This again points out the value of preventing the growth in the first place.

BLACK ALGAE

It is considered the most difficult algae to control. However, it is also likely the easiest to prevent. Black algae typically gain a foothold in areas of the pool that suffer from poor circulation. Areas such as corners or in certain areas of the deep end are often identified as places where black algae continue to show up in a particular pool and are then nearly impossible to eliminate. Most often, these areas suffer from inadequate circulation and thus little or no fresh water, sanitizer or algaecide gets to the area with any regularity. One of the best ways to prevent black algae growth or eliminate it once it surfaces, is to correct the circulation problem.

Once it begins forming, black algae develops specialized cells that lock it deep in the pores of pool surfaces. In order to effectively control it, all of its cells including those deep in the surface, must be killed. It is all but impossible for chlorine alone to get this deep into the pores of the pool’s surfaces. In addition to the attaching or locking mechanism of black algae, the growing colony also produces a defense mechanism. Outer layers of the colony produce a waxy coat that prevents chlorine or algaecides from penetrating into the colony and killing it. Therefore, the algaecide used should contain a “penetrating” agent. This agent will actually work to help the algaecide penetrate into the pores of the pool surface and cut through the waxy coat with a special wetting action that chlorine does not have.

The following steps will help in bringing black algae under control:

1. Correct any problems with the circulation pattern in the pool.

2. Brush the colonies as this will break through the waxy coating protecting the colony.

3. Add an algaecide intended for use on black algae.

4. Brush the colony daily thereafter, if possible, as this will remove any dead cells from the surface exposing the living cells underneath for exposure to the algaecide.

 

 

POOL START UP PROCEDURE

The following procedure should be used whenever a pool is being filled for the first time, refilled following maintenance or other major repair or when restarting the pool for the swimming season.

1. Before first filling a pool or adding substantial amounts of fresh water to the pool, either test the water using a good quality test kit or have it tested for pH, total alkalinity, calcium hardness and stain producing metals. This will tell you what type of treatment will likely be required once the pool is full and allow treatment measures to be taken that will prevent problems from the water source.
2. In cases where the pool is being reopened and was covered all winter, remove the cover carefully so as to avoid having any leaves or other debris fall into the pool. Sweep up and remove as much material as possible that may have accumulated in the pool during the off season.
3. In cases where the pool is being completely filled be certain to add a good sequestering agent as soon as the filling process begins. If the pool is already full, add the sequestering agent before any other steps are followed. This will tie up and inactivate any stain-producing metals that may be in the fill or pool water. This should be done even if the water analysis did not show the presence of these metals in the water sample. Note: If the pool construction happens to be black plaster, the sequestering agent should not be added until the pool is completely full.
4. Add a clarifier to the water. The clarifier will help the filter remove the very tiny particles that enter the pool in the filling process or that may remain following construction and installation.
5. Start the pump and filtration equipment and allow the water to circulate for 24 hours, if practical. This will assure that the sequestering agent and clarifier have been completely mixed in the water thus avoiding stain formation, cloudy or colored water.
6. Shock / oxidize the pool using a quality non-chlorine shock oxidizer. This will destroy organic wastes in the water and keep them from interfering with the sanitizer or acting as a food source for algae. It will also help give the water a “polished” look.
7. Again test the water and adjust if needed to balance the water. pH should be in the range of 7.2-7.8, total alkalinity between 80-120 ppm and calcium hardness between 100 and 400 ppm.
8. Begin to add your desired sanitizer to the water following the manufacturer’s guidelines.
9. If using chlorine in an outdoor pool, stabilizer (cyanuric acid or stabilized trichlor tabs) should be added to help the chlorine last longer and work more economically. Consult label directions.
10. Add an algaecide. The algaecide will prevent any algae in the pool from growing even if the sanitizer used were to fail. The regular use of an algaecide will keep the pool looking clean and bright and help the sanitizer to work more efficiently.
11. Test the sanitizer residual and maintain at the recommended level.
12. The pool is now ready for use.

 

WEEKLY MAINTENANCE

Follow a regular maintenance program:

1. Vacuum the pool or use a robot to remove dirt and debris that has accumulated on the bottom. More frequent vacuuming can be beneficial but it should not be done less than once each week.
2. Check the pressure or vacuum gauges on a sand or Diatomaceous Earth filter to determine if the filter requires backwashing. Backwash following the filter manufacturer’s directions. At a minimum, it is recommended to backwash twice monthly for a short period of time. Note: Some manufacturers produce a product that helps remove deeply-set dirt during the backwash process. Such products may help in improving filter performance during the season. If the pool has a cartridge filter, the cartridge should be inspected to determine if cleaning beyond a simple rinsing is required. Regardless of filter type, if the media is unusually dirty, it should be cleaned with a quality filter cleaner made for pool filters.
3. Add water as needed. There should be plenty of water to prevent the skimmer from vortexing and sucking in air. Check and adjust pH and total alkalinity. Test sanitizer residual, adjust as needed and refill feeders as required.
4. Add a sequestering agent every week. Even if metals are not detected in the water tests they can contaminate when least expected and calcium can precipitate to form scale or cloudy water. The small amount of sequestering agent used weekly will be far less costly than the expense incurred in acid washing or stain removal.
5. Add a maintenance dose of clarifier or products like c-pool to help the filter in removing even the smallest particles that can otherwise lead to hazy water conditions.
6. Shock oxidize the water once a month using a non-chlorine shock oxidizer. Regular shock oxidation will help prevent the formation of combined chlorine, red eyes, odors and skin irritation. The shock treatment will also help the sanitizer work better.
7. Add a maintenance dose of algaecide or all-in-one products like c-pool. The algaecide will prevent algae growth even if the sanitizer system were to fail or in the event of heavy bather loads or rainfall.
8. Add an enzyme oil and grease digester or products like c-spa to help break up scum lines and reduce filter clogs.
9. Clean along tile lines, surrounding pool areas and patio furniture.

 

SALT GENERATOR POOL MAINTENANCE

Hazardous to handle and store, chlorine can irritate the skin and the eyes. It’s no wonder, then, that many people opt for salt water pools, which offer some big advantages over traditional chlorinated swimming pools.

Salt Water Systems vs. Traditional Chlorinated Pools

Salt water pools aren’t as salty as seawater. In fact, they have only about one-tenth the salinity. Second, they aren’t completely chlorine-free because they are, in fact, chlorine pools. Instead, the system uses a process called electrolysis to create chlorine, which disinfects the water.

What are the Pros and Cons of a Salt Water Pool?

Salt Water Pool Advantages

• Because they have lower chlorine levels, salt water pools are much gentler on the eyes and skin.
• Traditional chlorine pools require owners to store and handle chemicals.
• Salt water pools produce softer-feeling water, which many find desirable.
• Because the salt cells produce chlorine on a trickle basis as needed, the pools require less vigilance to maintain chlorine levels compared to traditional chlorinated swimming pools.

Disadvantages of Salt Water Pools

• Salt water pools require a larger initial investment, and reinvestment after about 8 years,  making them much more expensive than traditional pools.
• More complex than traditional pools salt water pools often require experienced technicians even for minor problems.
• Salt can cause damage to certain materials, so you may have to avoid using specific types of heaters, fixtures, underwater lighting, liners and even some types of masonry work.
• The generating cells require special chemicals to prevent cell damage over time.

What is a Salt Chlorine Generator?

The primary piece of machinery in a salt water pool is the salt chlorine generator. Using electrolysis, the generator breaks dissolved salt into hypochlorous acid and sodium hypochlorite, two sanitizing agents used in chlorine-based swimming pools. The continuous process also prevents the buildup of chloramines.

A salt chlorine generator is often incorrectly called a salt water filter. This is inaccurate, as the generator does not filter pool water. A separate salt water filter removes debris from the pool.

What Kind of Salt Does a Salt Chlorine Generator Use?

Three types of salt are used with salt chlorine generators: solar salt, mechanically evaporated salt, and mined salt.

• Solar salt is derived from seawater evaporated by the sun, and contains impurities such as dead brine shrimp and bactertis. Impurities make the salt generator (and the salt water filter) work harder.
• Mechanically evaporated salt is also made from sea water, but generated heat is used to evaporate the water instead of sunlight, which burns of organic matter. Mechanically evaporated salt may, however, include pool-damaging minerals.
• Mined salt is dug from the ground, and is considered the purest form of salt.

How Much Salt Does My Pool Need?

The amount of salt your pool requires depends on the level of salt needed for your salt chlorine generator to function properly. Check the owner’s manual to find this amount–it usually ranges from 3,000 to 4,000 ppm (parts per million).

The number of gallons in your pool and its current salt levels determine how much salt to add. Use a salt water test kit to determine the pool’s current salt level, then calculate how much salt you need based on the pool’s size in gallons with a salt table, subtracting the current salt level (your generator manual should contain a salt table).

As an example, a 20,000 gallon pool with a current salt level of 500 Ppm would require 501 lbs of salt.

How Much Does a Salt Generator Cost?

A salt chlorine generator can usually be purchased for $600 to $800. Bear in mind the generator is only one part of the salt water pool system. With a salt water filter and other components,  a saltwater chlorination system costs between $2,500 to $3,500. To replace the system every ten years and the generator twice and purchase maintenance chemicals yearly would cost about $500 yearly.

How Long Does a Salt Chlorine Generator Last?

The salt cells used in most residential salt water pools are good for 10,000 hours of operation, or approximately three to five years. The life of a generator depends on multiple factors, including the frequency of pool maintenance, salt level, water chemistry, and other factors.

Maintenance

Salt generator pool maintenance is little different from other chlorine treated pools. It is important to realize that the generator does not replace anything in the pool except the need to add chlorine as this is made by the generator. For ease of maintenance, do the following:

1. Vacuum the pool or use a robot to remove dirt and debris that has accumulated on the bottom. More frequent vacuuming can be beneficial but it should not be done less than once each week.
2. Check the pressure or vacuum gauges on a sand or Diatomaceous Earth filter to determine if the filter requires backwashing. Backwash following the filter manufacturer’s directions. At a minimum, it is recommended to backwash twice monthly for a short period of time. Note: Some manufacturers produce a product that helps remove deeply-set dirt during the backwash process. Such products may help in improving filter performance during the season. If the pool has a cartridge filter, the cartridge should be inspected to determine if cleaning beyond a simple rinsing is required. Regardless of filter type, if the media is unusually dirty, it should be cleaned with a quality filter cleaner made for pool filters.
3. Add water as needed. There should be plenty of water to prevent the skimmer from vortexing and sucking in air. Check and adjust pH and total alkalinity. Test sanitizer residual and adjust the generator as needed to maintain sufficient chlorine level. Monthly: use a salt test kit to determine salt level and adjust if needed. Salt levels will not change rapidly and may only need more salt once or twice per season and in many cases not at all.
4. Add a sequestering agent every week. Even if metals are not detected in the water tests, they can contaminate when least expected and calcium can precipitate to form scale or cloudy water. The small amount of sequestering agent used weekly will be far less costly than the expense incurred in acid washing or stain removal. This will also help reduce scale buildup on the salt generator cell.
5. Add a cell protection chemical that helps reduce oil and grease buildup and protects and extends the life of the cell by reducing other scaling agents that are not inhibited with a standard sequestering agent.
6. Add a maintenance dose of clarifier to help the filter in removing even the smallest particles that can otherwise lead to hazy water conditions.
7. Shock oxidize the water using a non-chlorine shock oxidizer. Regular shock oxidation will help prevent the formation of combined chlorine, red eyes, odors and skin irritation. The shock treatment will also help the chlorine work better.
8. Add a maintenance dose of algaecide or all-in-one products like c-pool . The algaecide will prevent algae growth even if the generator system were to fail or in the event of heavy bather loads or rainfall.
9. Add an enzyme oil and grease digester or products like c-spa to help break up scum lines and reduce filter fouling.
10. Clean along tile lines, surrounding pool areas and patio furniture.

 

WINTERIZINGTHE POOL

Proper closing of the pool at the conclusion of the swimming season will help assure an easy opening for the next season. If the pool is not properly treated now the water and pool surfaces will all be heavily fouled when the pool is reopened and plumbing and equipment could be damaged, thus requiring significant time and expense to get the pool back into operation.

1. Brush the walls and floor and vacuum up all loose debris from the pool bottom.
2. Clean the filter or cartridges using a good quality pool filter cleaner. It will be far easier to clean the filter now than in the spring and will assure good filtration on start up.
3. If the water level is to be lowered for the winter, do so now and then proceed to step 4.
4. Completely drain all water from pipes, pumps, heaters, filters and other pool equipment to prevent damage due to water freezing. Use antifreeze especially made for pool use, if necessary.
5. Shock oxidize with a non-chlorine shock oxidizer. This will eliminate organic contaminants that would otherwise help support algae growth.
6. Add an algaecide to eliminate algae growth throughout the winter.
7. Add a sequestering agent to prevent any calcium precipitation or stains due to metals. The sequestering agent will also help protect any metal components and equipment.

Note: In mild climates where the pool is left full and uncovered for the winter, it is suggested that the filtration system continue to operate and the sanitizer, algaecide and sequestering agent be added regularly in addition to following steps 1 and 2 above.