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Chlorine: A Crucial Element of Safe Water

Chlorine Balance - BlogProper chlorination is a pivotal aspect of all aquatic facilities and plays the all-important role of killing harmful microorganisms and disinfecting water. Providing a crystal blue pool that delivers consistent chlorine levels is the goal of all aquatic facility operators—and chlorine is the catalyst to make that a reality.

Yet, just as is the case with pH levels, there is such thing as too much chlorine. In fact, chlorine levels exceeding 4 parts per million (ppm) indicate excess chlorination.

Specifically, a pool’s free available chlorine (FAC)—the portion of the total chlorine remaining in chlorinated water that has not yet reacted with contaminants—should be in the range of 2 – 4 ppm. Chlorine levels that climb to 5 ppm are still acceptable to swim in, but anything over 10 ppm is highly unsafe to swimmers and can also lead to damaged equipment.

While chlorine levels should be tested at least once each day, there are certain telltale signs that indicate your aquatic facility’s chlorine level is too high. Swimmers that come in contact with too much chlorine can experience a burning sensation on their skin, while the gases given off by the evaporation of water that is oversaturated with chlorine-based cleaning solution can also lead to eye and nose discomfort. Even worse, rare cases can also lead to chlorine poisoning.

How Low Can You Go?
Keeping in mind that 2 ppm is the lowest recommended level of FAC, chlorine levels should also never fall below 1 ppm to protect swimmers against excess bacteria while removing algae from the water.

Just as it is important to test each day for chlorine levels, testing for pH levels is just as important and has a direct correlation to the amount of chlorine in water. Water levels above the recommended limit of 7.8 pH have a negative effect on chlorine as it takes away from chlorine’s disinfecting qualities, leaving swimmers exposed to contaminants.

Additionally, the notion that being able to smell a pool’s chlorine indicates that chlorine levels are too high is only a myth. In fact, it is the opposite, as this usually means that a shock treatment may be required to boost chlorine levels.

For more information on the importance of water balance, visit

Topics: Aquatic Facility Management

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