What Are the Best Hot Tub Chemicals?

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Hot tubs are popular for relaxing and soothing tired muscles at home, but they are also expensive and require constant maintenance. Because the water is heated and people go in and out, carrying bacteria into the water from their skin, your hot tub can get filled with bacteria. Bacteria thrive in warm water, which means hot tubs must be kept clean and the bacteria must be killed to avoid infection. Using several different chemicals will do the trick, but chemical levels have to be measured to assure the correct levels. Chemicals should only be added when the hot tub is not in use, and when the water is warm and on a low agitation speed so that the chemicals will be dispersed evenly.



There are two chemicals used to sanitize the water in hot tubs: chlorine and bromine. Both chemicals come in tablet and granule form. Only buy chemicals designed for use in hot tubs. Never add any chemicals if people are in the hot tub. Bromine actually comes in a couple of different types. Sodium bromide must be used with an activating agent such as potassium monopersulfate or chlorine. BCDMH does not need any activators. It is a combination of bromine and chlorine, which makes it self-activating. Because bromine does not give off the strong odor that chlorine does, it is preferred by many people.


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Ozone is an oxidizing chemical that kills bacteria in hot tub water. A special device called an ozonator converts regular oxygen into ozone and disperses the ozone into the water. Even though ozone will kill bacteria, you will still need to use low levels of chlorine and bromine to completely sanitize the water. Ozone does not interfere or react negatively with the other chemicals, so it is safe to use.


pH Balancing Chemicals

Maintaining the pH level of your hot tub is as important as maintaining the sanitizer level. The ideal pH level is 7.0, which is neutral. Acidic water, with a pH level below 7.2, is strong enough to damage pumps and filters. Water that is too alkaline, with a pH level above 7.8, will create a build-up of scale. To increase the pH level, you will need to add an alkaline compound like bicarbonate. For every 500 gallons of water, 1/3 cup of bicarbonate is added to raise the alkalinity by 20 parts per million. To lower the pH, acid needs to be added. The most common solution is muriatic acid, which is hydrochloric acid.


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