Which of the following pH levels is considered ideal for chlorine effectiveness?

The ideal pH level for chlorine effectiveness in water treatment is around 7.2. At this pH, chlorine remains highly effective as a disinfectant while minimizing the formation of chloramines, which can occur when chlorine interacts with ammonia in the water. Chloramines are less effective at killing pathogens than free chlorine and can lead to issues such as unpleasant odors and skin irritation.

At a pH lower than 7.2, chlorine becomes more effective; however, it may also lead to increased corrosiveness, potentially damaging pool or system equipment. Conversely, if the pH rises to levels above 7.2, chlorine's effectiveness decreases and its ability to neutralize pathogens diminishes. Therefore, maintaining a pH around 7.2 balances effectiveness and safety in water treatment processes.