Which chemical is commonly used in swimming pools to control pH levels?

The chemical commonly used in swimming pools to control pH levels is sodium bicarbonate, which is also known as baking soda. This substance is effective in raising the pH levels of pool water, making it less acidic and helping to stabilize the overall balance of the water chemistry. Maintaining an appropriate pH level is crucial for swimmer comfort, sanitizer effectiveness, and the longevity of pool equipment.

Sodium bicarbonate acts as a buffering agent, meaning it helps to resist drastic changes in pH, which can be caused by factors such as rain, swimmer activity, and the addition of chemicals. By ensuring that the pH remains within the recommended range of 7.2 to 7.8, sodium bicarbonate plays an essential role in the overall maintenance and safety of swimming pools.

In contrast, other options such as sodium hypochlorite and calcium hypochlorite are primarily used as disinfectants rather than pH adjustment agents. Cyanuric acid is used to stabilize chlorine in outdoor pools but does not directly affect pH levels. Thus, sodium bicarbonate is the appropriate choice for controlling pH in swimming pools.