Swimming Pool Chemicals From Poolplaza

What is involved in Pool Water Care

A.  Chlorine (or other sanitizers) The first step in pool water chemistry is to get something into the water to sanitize the water and burn up all the contaminants. The most common oxidizer/sanitizer is chlorine.  As an oxidizer, it literally burns up organic material in the water.  This is important because by burning up that material, it greatly reduces the load on the filter.  As a sanitizer it kills germs in fairly short order, usually milliseconds. It is important to maintain a "chlorine residual" in the pool water at all times.  In other words, you need to keep between 2.0 and 4.0 parts per million of chlorine in the water.  To maintain proper chlorine levels, there are three steps: Step One:  Maintain a constant chlorine feed - this can be done in several different ways. Hand feeding is by far the most difficult and least dependable method.  This involves adding chlorine manually to the pool at regular intervals as needed to keep your chlorine level between 2.0 and 4.0. Tablet Feeders are a very common way to feed chlorine into the pool.  A floating chlorinator is the least expensive.  An inline chlorinator is still fairly inexpensive and keeps the chemicals away from swimmers. Salt Water Chlorine Generators are growing in popularity, and are a very good way to go.  If you have never heard of this before, take a moment to visit our salt water page and you will see why so many people have chosen to go this route.  Step Two:  Test Regularly - this can be done using a simple test kit or test strips.  We recommend testing the water chemistry at least once per week and more often during times of heavier usage.  Follow the instructions that come with the kit. Step Three:  Superchlorinate as needed - there are several instances in which it is important to superchlorinate (shock) a swimming pool. If the chlorine reading gets too low then it is important to superchlorinate the pool in order to quickly raise up the chlorine level to avoid unsanitary water. If algae develops, it is a good idea to temporarily raise the chlorine level to 10 ppm and brush the entire pool down to expose the algae. After a heavy rain, if a lot of rainwater and other contaminants have washed into the pool, it is a good idea to shock the pool.  These contaminants tend to use up the chlorine and you need to superchlorinate the pool to meet the extra demand. There are other sanitizers on the market, but we have found chlorine to be the most cost effective strategy available for the homeowner today. Bromine is often used on spas, but it still contains about 30% chlorine in the tablet and there are issues of corrosion on outdoor pools caused by the hydantoin (ammonia) base in the bromine tablets.  Biguanides are also another option, but most of the time we hear about people who got tired of spending the bucks on biguanides and were looking to get back to chlorine (making the conversion back to chlorine is not easy). B.  PH Balance  The concept of pH balance is one which can be confusing, but it is actually fairly simple.  Water can be either acidic (low pH) or basic (high pH) or balanced (neutral pH). If water has a low pH (below 7.2), it is acidic and will cause corrosion and etching.  If water has a high pH (above 7.8), it is basic and can cause cloudy water and scaling on pool surfaces.  We recommend keeping the pH between 7.4 and 7.6. The two keys to maintaining a proper pH are this: First, keep your total alkalinity (below) at the proper levels because if your total alkalinity is correct, then your pH is less likely to bounce all over the place. Second, test and adjust regularly.  It is better to make minor corrections more often than it is to make a major correction.  Soda ash is used to raise the pH and Muriatic Acid is used to lower the pH.

C.  Total Alkalinity  The total alkalinity is like a pH buffer.  It is a reserve of alkaline materials in the water that helps to resist pH change in the water.  The reality is that as soon as the pH becomes acidic, the water will immediately begin to try to balance itself.  Obviously we would much rather have it attack the Total Alkalinity than to have it attack the plaster or the pool equipment.  Some of the alkalinity is sacrificed to help the pH balance itself. Maintaining proper total alkalinity level does not eliminate the need to test and adjust the pH levels, but it does reduce "pH bounce" and helps to reduce corrosion and etching in the pool.  If the Total Alkalinity is too low, then you can add Baking Soda (Sodium Bicarbonate) to the pool to raise the alkalinity.  If the Total Alkalinity is too high, then you can add Muriatic acid to the pool to lower the alkalinity. When the alkalinity is too high, then the water will cloud up easily (after shocking with Calcium Hypochlorite, for instance).  This is because the water has so much alkaline material in it that it cannot dissolve any more very easily, so the undissolved alkaline material goes into suspension rather than solution.  The suspended alkaline particles make the water very cloudy.

D.  Calcium Hardness  Calcium Hardness should be measured at least once per month and should be maintained at 250 parts per million or higher.  If it is low, then it should be raised by adding calcium chloride to the pool.

E.  Stabilizer  Stabilizer slows down the reaction of the chlorine slightly so that the sunlight does not dissipate it so quickly.  An unstabilized pool will use up chlorine very quickly on a sunny day.  Stabilized chlorine tablets (trichlor tablets) contain 50% stabilizer by weight!!  This means that for every pound of chlorine tablets, you are adding 1/2 lb. of stabilizer.  The ideal range for stabilizer is between 30 and 60 parts per million.  If it is too low, then the sunlight will dissipate the chlorine easily and quickly on a sunny day.  If it is too high, then the effectiveness of the chlorine is greatly reduced, and the reaction time is slowed considerably.  This can be a major contributing factor to yellow algae problems. If the stabilizer level gets too high, then there are two options available: The first option is to drain the pool and refill with fresh water.  Possible variations would be to drain partially and refill or backwash longer each time to help to turn over the water.  The second option would be to use sodium bromide water treatments to counteract the effect of the stabilizer.