What chemical is added to lower the pH level in pool water?

Muriatic acid, also known as hydrochloric acid, is commonly used to lower the pH level in pool water. Maintaining the correct pH range (between 7.2 and 7.8) is crucial for effective sanitation, swimmer comfort, and preventing damage to pool equipment. When the pH level is too high, it can lead to issues such as cloudy water, scale formation, and reduced effectiveness of chlorine. Adding muriatic acid directly decreases the pH by increasing the number of hydrogen ions in the water, effectively balancing the chemistry.

Sodium carbonate, also referred to as soda ash, is used to raise pH levels, not lower them. Calcium hypochlorite is primarily a disinfectant that adds chlorine to the water but does not significantly affect pH levels. Potassium chloride is often utilized as a salt alternative or to replace sodium, and it does not influence pH directly. Therefore, muriatic acid is the preferred chemical for correcting high pH levels in pool maintenance.