Water Chemistry Certified         


                                           Caution: NEVER mix chlorine and muriatic acid as it will produce a very toxic chlorine gas.

        In the swimming pool water muriatic acid and chlorine work wonders together but as a 'gas' type vapor it is dangerous to your health.


Ph is the measure of  acidity in the water. Technically it is an inverse measure of the hydrogen ion activity of the water. Adding acid creates more hydrogen ion activity resulting in a lower Ph reading. The Ph scale ranges from 0-14. 7 is neutral. Anything below 7 is considered acidic anything above 7 is base or basic.

In swimming pools 7.4 to 7.8 is considered to be the idea range in which to maintain the Ph level. If the Ph is allowed to remain high (8.0) or higher for a prolonged period of time, calcium in the pool will combine with the carbonates in the pool to form scale. Calcium carbonate appears in the form of rough unsightly deposits on the pool surface and tile. Maintaining the proper Ph level  will help slow the formation of scale. The Ph of the pool should be tested every week. If the Ph tests high , muriatic acid should be added. Do not add acid in front of a skimmer or by any metals, lights, rails, etc. The amount of acid to add is determined by using the chart that comes with a standard test kit.

If the Ph tests below 7.0 the is considered acidic. This is a problem that must be corrected immediately! Acid in the water will erode any metals in the system, mainly brass in the pump and more so the copper in the plumbing and the heater. When acid attacks the copper in the system it very quickly returns it to the pool in the form of copper sulfate which causes green and turquoise stains on the plaster. There is no way to remove these stains without draining and acid washing the pool. If the Ph should fall to low it can be raised quickly by adding soda ash to the water.


The total alkalinity is a measure of the total of the hydroxide ions, carbonate ions, and bicarbonate ions in the water expressed in parts per million (P.P.M.). Total alkalinity may be defined as the buffering capacity of water or the ability of the water to neutralize acid. A very small amount of acid will cause a very large drop in Ph if that pool has low alkalinity. If the pool has high alkalinity, it will significantly more acid to cause the equivalent drop in Ph level. If too much acid is accidentally added to a pool, the alkali in the water will act as buffer by neutralizing some of the acid and giving some protection to the metals in the pool system. However, if the alkalinity is low and too acid is added to the pool, the acid will immediately begin aggressively attacking any metals in the pool system. The alkalinity should not be allowed to fall below 80 P.P.M. Ideally it should be 100 P.P.M. or higher. To raise alkalinity add baking soda (sodium bicarbonate) or "alkalinity" according to instructions on container. "Alkalinity" will raise the alkalinity substantially with only a small effect on the Ph level. Conversely, soda ash will raise Ph substantially with only a small effect on the alkalinity.  The alkalinity levels tend to be very stable on pools and usually only need to be tested every month or so.


Chlorine is added to pool water as both a disinfectant (it will kill germs, viruses, micro organisms) and as an oxidizer, it will actually break down organic debris into basic components which can gas out of the water resulting in cleaner, clearer water. The main reason for maintaining a proper chlorine level is to avoid problems with algae, cloudy water, and dangerous bacteria and viruses. The ideal range marked on a test kit is 1.0 to 1.5 P.P.M. chlorine, however maintaining a stronger chlorine level of 3.0 or higher is recommended with weekly service. Algae problems tend to occur less frequently and in smaller degree when 3.0 or level is maintained. Algae problems are unsightly, expensive and time consuming to clean up. By maintaining the chlorine level at 3.0 or higher it is much easier to avoid the problem in the first place.

There are many types of chlorine. In its natural state chlorine is a gas. This is the strongest and cheapest form of chlorine. However because chlorine gas is highly toxic and hazardous to store and work with, its use around swimming pools is rare.  Chlorine tablets and liquid chlorine are the most common forms of chlorine. Chlorine tablets (trichlor-s-trizinterone) are a cleaner stronger form of chlorine (99% active ingredient). When used in residential pools they are placed in a plastic floating dispenser. The tablets slowly dissolve and provides for ideal time release of chlorine into the pool. The number of tablets placed in the dispenser each week is determined by the anticipated amount of chlorine demand. Liquid chlorine is used to raise the chlorine level quickly. Liquid chlorine has a high Ph (14.0) so careful monitoring of Ph levels are required when adding this form of chlorine.

There are many factors that will cause the chlorine to leave the water more quickly than normal.

1. Warm water: Chlorine is very stable in cold water. The warmer the water is, the more quickly the chlorine will leave the water.

2. Sunlight exposure: Chlorine is stable in darkness. The more hours of  sunlight exposure there are with the water, the more quickly the chlorine will leave the water.

3. Bather load: The ammonia introduced into the water by a bathers sweat or urine is a strong chlorine neutralizer. The more the swimmers are in a pool (especially young children) the more quickly the chlorine will leave the water.

4. Organic debris: Leaves, bugs, algae, cloudy water etc. all are targets for the chlorine to oxidize, which in turn uses up the chlorine.

Cyanuric Acid:

Cyanuric Acid is a chemical that is added to pool or spa water to help the chlorine stay in the water longer. C.A. is very stable, once added to pool water it will remain for several months. C.A. levels should be ideally range from 50 p.p.m. to 100 p.p.m. Levels above 100 p.p.m. tend to be less effective because the C.A. keeps the chlorine in the water by locking on to one of the active sights on the chlorine molecule. When the C.A. level is to high it locks up to many active sights on the molecule. This reduces the chlorine's potential to act as an oxidizer and disinfectant, even though there may plenty of chlorine in the pool water. The only way to reduce C.A. levels is dilute the water by draining and refilling the pool. The amount of water to drain is determined by the current C.A. level and the target C.A. level. If the C.A. is tested at 100 p.p.m. and the target was 50 p.p.m. you would drain half the water and refill it.

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