How much chlorine is needed to add to a pool?

How Often Do I Add Chlorine to My Pool?

• Answer:

  In a swimming pool, maintaining the proper chlorine level is important for overall pool sanitation and safety. Because it's a strong chemical, only a small amount is needed in a swimming pool. A commonly asked question among swimming pool owners has to do with how often to add chlorine disinfectant to their pools. While chlorine needs to be added both regularly and as needed, pool owners should add chlorine when levels begin dipping below 2 ppm. Chlorine Dosing At minimum, a swimming pool should be tested at least twice weekly for chlorine levels. Once a pool is tested for its free available chlorine level, you can decide whether to add chlorine. You may need to test more frequently if your pool is exposed to regular rainfall, for example. Chlorination Levels If the chlorine level in your swimming pool is about 2 parts per million (ppm), there's no need to add chlorine. A recommended effective working range of pool chlorine is 2 to 4 ppm. In all cases, pool owners should add chlorine when levels begin dipping below 2 ppm. Special Reasons Other reasons why it's necessary to occasionally add more chlorine have to do with weather. For instance, chlorine levels typically decline if a pool has been exposed to overnight rainfall. Another weather-related reason for reduced chlorine is heavy sunlight; lots of sun on a pool usually requires more frequent chlorination. Considerations It only takes from 3/4 to 1 lb. of standard calcium hypochlorite pool chlorine to maintain a 30,000-gallon pool at 2 ppm of residual chlorine. After testing, if chlorination is needed, add only enough to raise chlorine levels back to 2 to 4 ppm. Pool chlorine should never be allowed to fall below 1 ppm. Ensure your pool's pH is between 7.2 and 7.8, because pool chlorine works better when pool pH is balanced.