Swimming Pool Chemicals

Pool Water Balancers

In Addition to maintaining the chlorine level of swimming pool water, the pool pH, pool Alkalinity, chlorine stabilizer (Cyanuric Acid), and pool Calcium Hardness levels must also be properly maintained to keep pool water clean and safe for swimmers. If these pool chemical levels are not occasionally tested and properly maintained the result will be poor water quality, wasted chemicals, irritation to the skin and eyes of swimmers and damage to pool surfaces and equipment. Follow this link to purchase pool chemicals from our preferred online pool supply retailer.

pH & Alkalinity

The pH and Alkalinity levels of swimming pool water affect many areas of the swimming pool and must be kept at the correct levels if you expect to successfully maintain your swimming pool. The Alkalinity of pool water acts as a buffer for the pH, and helps prevent the pool pH level from fluctuating. The Alkalinity should be maintained at 80 - 120 ppm. The pH is the measure of the acidity of the swimming pool water, and the pH level should be maintained at 7.2 - 7.6 ppm. The pH of pool water is somewhat sensitive, but easily controlled if the Alkalinity is kept in range. If the pool pH level is not kept in range the pool water will irritate the skin and eyes of swimmers, corrode the pool surface and inside of the equipment and make it very hard to maintain the chlorine level of the swimming pool. All basic test kits should read the pH and Alkalinity level of pool water, and these levels are easily adjusted with common water balancers.


The chemical name of pool "Stabilizer" is Cyanuric Acid and is commonly referred to by either name. The Stabilizer level of swimming pool water must be maintained at 30-50 ppm. The Stabilizer level is important, but is typically only tested at the beginning of the swimming season when a pool is opened. The Stabilizer in swimming pool water partially surrounds the chlorine in pool water on a molecular level, to protect the chlorine and prevent the chlorine from being quickly burned off and used up by the sun.

The symptoms of having too much Stabilizer and having too little stabilizer in your pool water are very similar, and if you experience problems maintaining a chlorine level when all other chemical levels are properly balanced the stabilizer level should be tested. If the Stabilizer level tests lower than 30 ppm it will be difficult to maintain a chlorine level, because any chlorine added to your swimming pool will quickly evaporate and burn off in direct sunlight. If the Stabilizer level tests above 50 ppm it will also be difficult to maintain a chlorine level. Rather than partially surrounding the chlorine in your pool water to protect the chlorine, too much stabilizer will completely surround the chlorine making it inactive. In this state the chlorine is unable to combine with bacteria and harmful contaminants to sanitize your swimming pool, and when you test for free chlorine you will get a reading of zero.

Stabilizer can be added to a swimming pool if necessary to raise the level, however once Stabilizer is present in pool water it cannot be easily removed. To reduce the level of Stabilizer in a swimming pool, the pool water must be diluted by partially draining the pool and re-filling with fresh water. 25% of the pool water should be drained and replaced with fresh water. The pool should be circulated for 12-24 hours, and the Stabilizer level should be tested again. This process should be repeated until the Stabilizer tests within range.

The chlorine tablets and granular chlorine used by most pool owners is a pre-stabilized form of chlorine. This means that the chlorine contains a small amount of stabilizer, and each time chlorine is added to the pool a very small amount of Stabilizer is added. This small amount of Stabilizer added with chlorine typically does not cause problems in outdoor pools because water is splashed out or evaporates, and fresh water is periodically added which dilutes the Stabilizer. The common pre-stabilized form of chlorine should not be used in an indoor swimming pool because much less evaporation occurs. The small amount of stabilizer added with common chlorine tablets will build up in an indoor swimming pool and cause problems. Indoor swimming pool owners need to use an un-stabilized form of chlorine.

Calcium Hardness

The calcium hardness of swimming pool water refers to the amount of calcium present in the pool water. The calcium hardness should be maintained at 80-150 PPM in a pool with a vinyl liner, or 150-200 PPM in a concrete or plaster finish pool. Low levels of calcium hardness can lead to corrosive water conditions. Corrosive water conditions damage the pool surface, pool equipment and pool plumbing. If your pool has a plaster or masonry finish the corrosive water will absorbing calcium from the pool walls and floor, eating away at the pool surface until the hardness level nears 150 ppm. The calcium hardness level can be easily raised using a Calcium Hardness Increaser available from most pool supply companies.

If the calcium hardness levels are high, this will lead to cloudy pool water and "scaling". Scaling is most visible around the water line of a swimming pool as a white chalky deposit, but also forms inside pool equipment and pool plumbing. A pool Calcium Hardness Reducer chemical is available from most pool supply companies to lower the hardness to the desired range for your pool. You may also partially drain and refill a swimming pool with fresh water, which has a lower Calcium hardness level.

Calcium is added to a swimming pool in the water used to fill the pool and in the pool chemicals used to treat the water. The main pool chemical that adds calcium to pool water is standard chlorine pool shock (Calcium Hypochlorite). If you find that your calcium hardness level is too high, read the label of your pool shock and you may find that the active ingredient is Calcium Hypochlorite. Each time this pool shock is added to the pool water, calcium is added to the water. To resolve this problem Chlorine-Free Pool Shock should be used on a regular basis, instead of the standard chlorine pool shock (Calcium Hypochlorite). The active ingredient in chlorine-free pool shock is Potassium Monopersulfate. This does the same job of oxidizing bacteria and harmful organics in pool water, however Chlorine-Free Shock does not contain any calcium. If you choose to switch to chlorine-free shock you should always still keep the standard chlorine pool shock on hand, because it is the only pool chemical that can


Chlorine and Bromine

Pool Shocks

Algaecides, Clarifiers & Enzymes

No/Low Chlorine