Balancing Your Swimming Pool Chemistry

By: Glenn Whitehead

pool chemistryMonitoring and maintaining proper swimming pool chemistry is the most important element of swimming pool care. While this leaves many people baffled; it's really not that complicated. The first step of the process is to regularly test the water. During the summer months, this should be done either daily or every other day. In the winter you can probably get by with once a week. If you maintain a regular schedule of testing the water and adjusting the chemical balance accordingly; it should require a minimal amount of time. However if you neglect the job, you run the risk of algae growth and possible damage to your pool and equipment. Learning the following basics will help you avoid difficult cleaning jobs and expensive repairs.

  • Chlorine-This is the one everyone knows. Chlorine is the chemical that sanitizes the water, kills bacteria, and prevents algae growth. Pool chemistry is measured in parts per: million gallons of water which you'll see abbreviated as (PPM). The desired chlorine range is 0.5 to 3.0 PPM. If  levels drop below this range you run the risk of discolored, murky water and algae growth. If above the acceptable range; the water may irritate the eyes and skin. Adding chlorine to the water is generally done with tablets or granular chlorine through an automatic inline chlorinator. There are also floating chlorinators, but the inline models are preferable because of the ability to regulate the amounts that are dispersed. Occasionally, it will be necessary to super chlorinate or shock the water. The is done as a preventative measure against algae and bacteria. How often you need to do this will depend on the amount of use and the weather conditions. When shocking the pool; allow the chlorine level to return to normal before allowing swimmers. During summer months and warm temperatures chlorine is burned quickly by the heat and sunlight. It's crucial to stay on a regular schedule because the water color will turn quickly when the levels drop and, once it turns, it will take a lot of work to get it back.
  • PH-This is the acidity level of the water. When testing the PH level the acceptable range is 7.2 to 7.6 PPM. PH may be the most important element of swimming pool chemistry because of it's effect on the other elements and the potential damage it can cause. Low PH can cause high acidity of the water resulting in corrosion of metal components, etching of plaster, and staining. Having low PH is also the most common cause of burning to the eyes and will speed up the burning of chlorine. High PH limits the effectiveness of the chlorine and may cause the water to become cloudy. To lower the Ph level add muriatic acid to the water by pouring around the perimeter of the pool. Be careful to stay away from ladders or other metal components due to the highly corrosive nature. It's a good idea to then brush the pool to keep the acid from settling on the plaster. The PH can be raised by adding soda ash (sodium bicarbonate). Chemicals should always be added according to the manufacturers instructions and the MSDS.
  • Total Alkalinity-In technical terms is a measure of the waters ability to neutralize or dissolve the hydrogen ions in acid. Basically, having the desired alkaline level helps control fluctuations in PH when chemicals are added. The desired Total Alkalinity level is between 80 and 120 PPM. Low levels will cause drastic fluctuations in PH, which can be damaging to pool equipment. Higher levels make it difficult to adjust PH and render chlorine less effective. Total alkalinity can be raised byadding sodium bicarbonate or soda ash and can be lowered by adding muriatic acid or sodium bisulfate. Consult the manufacture's instructions for the proper amounts of chemical to be added.
  • Calcium Hardness-This is the measure of dissolved calcium in the water. The desired levels are between 250 and 500 PPM. Maintaining the desired levels is important for the protection and life of the plaster. Lower levels will cause calcium to leach from the plaster causing pitting and shortening the lifespan of the surface. High levels may cause scaling and cloudy water. To raise calcium hardness, add calcium chloride. To lower the level, add small amounts of trisodium phosphate of backwash water from the pool and replace with fresh.
  • Stabilizer (Cyanuric Acid)-Chlorine molecules are unstable and exposure to sunlight and heat will cause the to dissolve rapidly lowering the amount of free chlorine.Cyanuric Acid or (stabilizer)hepls prevent drastic fluctuations in swimming pool chemistry Adding cyanuric acid stabilizes the molecules, slowing the dissipation of the chlorine. In other words, adding stabilizer reduces the amount and frequency of adding chlorine to the pool. Some chlorine tablets are stabilized, so you may already have some level of cyanuric acid. The desired level is between 30 and 50 PPM. Cyanuric acid should be added in small amounts to avoid exceeding 50 PPM. Extremely high levels can cause a chlorine lock, which prevents the chlorine from doing it's job, causing the water to cloud or become discolored.
Learning to monitor and control these basics of swimming pool chemistry will give you a good start on keeping a clean attractive pool year round. For a complete guide to swimming pool care and eliminating the need for a maintenance service, take a look at The Ultimate Swimming Pool Guide. . Written by well known pool expert Terry Duff, this is an excellent resource for keeping a beautiful pool and saving time and money.

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