Essential Guide on Mastering Swimming Pool Chemicals

by Pool Builders on 01-13-2011 in Articles

Knowing how to maintain water chemistry is the key aspect to a healthy and attractive swimming pool. You will also save a significant amount of money and lots of valuable time by understanding how swimming pool chemicals work.

The following guide outlines the simple steps and crucial facts involved in water treatment so that you can give your swimming pool that same care as a pricey professional.

Step 1 - Choose the right chlorine for effective sanitisation

The chemical chlorine is the main way most pool owners use to keep their water clean. Chlorine kills harmful contaminants by combining with bacteria and other unsanitary organics in the water on a molecular level; these are then removed by your pool filter system. Once the chlorine has bound itself to the contaminates, it then becomes inactive and no longer works to sanitise your pool, meaning more needs to be added on a weekly basis to continue the effect.

There are many types of chlorine on the market, so without the right know-how it is difficult to determine what type you should use. Chlorine is available in granular form, sticks,1" tablets and 3" tablets. It's a good idea to buy the slow release tablets which have binders and fillers that keep them together rather than the ultra cheap versions - you will notice the difference as they dissolve because the cheap tabs and sticks tend to crumble or fall apart within 2 - 3 days instead of gradually and more effectively dissolving while maintaining their shape.

The main thing to look out for is the concentration of the active ingredients. It's recommended you choose a concentration of 56% to 62% Sodium Dichloro-S-Triazinetrione in granular chlorine, and 90% Trichloro-S-Triazinetrione in chlorine tablets or sticks. Granular Chlorine can also be in the form of Calcium Hypochlorite and is normally only available in volumes of up to 65%.

Step 2 - Add the chlorine to your pool

Choose either a floating chlorine feeder or automatic chemical feeder, available from any pool supply distributor, to automatically dissolve 1 inch chlorine tablets, 3 inch chlorine tablets or chlorine sticks into your swimming pool water. Chemical feeders slowly ration out precise amounts of chlorine automatically, providing precise control over the amount of chlorine being added to your swimming pool. It's a no-no to simply dump chlorine tablets or chlorine sticks into the pool, or place chlorine tablets or chlorine sticks in the skimmer basket. This is because if a chlorine tablet dissolves directly in your skimmer basket, all of the water passing through your pool plumbing and circulation system carries a high level of chlorine which will slowly eat away at the inside of the pool's circulation system and cause premature failure of your pool pump and filter components.

Step 3 - Achieve the correct water pH level

Maintaining the right pool pH level can be just as important as having correct chlorine amounts, because it determines how effective the chlorine will be. The pH level of your swimming pool should be between 7.2 - 7.6. Chlorine is about 10 times more effective at sanitising your water when the pH is at 7.2 (the same level as human tears). If you find the water pH level is too high, you can most effectively lower it by slowly pouring "Muriatic Acid" (otherwise known as Hydrochloric acid) directly into the deep end of the pool while the pool pump is on and the water circulating. This chemical can be highly harmful if it gets on the skin - if you're worried about any accidents, Granular acid or pH Minus is a safer alternative.

Step 4 - Monitoring pH levels

Your pool's pH can best be measured with a "drop" type test kit instead of a "test strip" test which can easily be misread. Whether you need to increase or decrease the pH level, you should add smaller amounts of chemicals then retest after about 6 hours of continuous filtration to prevent fluctuations known as "bouncing". If you have a true pH bounce problem, that is typically due to low alkaline levels.

If swimming in your pool causes your eyes to burn, this is often caused by the pH being either too high or too low. Thus, monitoring pH levels is important if you want to avoid red, irritated eyes.


Using the right Swimming Pool Chemicals and maintaining their correct levels is crucial to both the upkeep of your swimming pool and your ability to safely enjoy it. The above information gives you the most important fundamentals to accomplish this so that you can do it yourself instead of spending a small fortune hiring professional help.

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