To lower the pH of swimming pool water, which chemical may be added?

Muriatic acid, also known as hydrochloric acid, is commonly used to lower the pH of swimming pool water effectively. When muriatic acid is added to pool water, it reacts with the alkalinity and helps bring the pH level down to the desired range, typically between 7.2 and 7.8. Maintaining the pH within this range is crucial for swimmer comfort, effectiveness of sanitizers, and overall water quality.

Hypochlorite acid is not a typical term used for swimming pool chemicals, and it may not effectively lower pH directly. Sodium chloride, or table salt, is used for saltwater pools primarily for generating chlorine through electrolysis and does not impact pH levels significantly. Soda ash, on the other hand, serves to raise pH levels rather than lower them, making it unsuitable for this purpose. Thus, the use of muriatic acid as a pH decreaser is both effective and appropriate for pool maintenance.