Which substance is added to raise pH in a pool?

Soda ash, chemically known as sodium carbonate, is used to raise the pH level of water in a swimming pool. Maintaining the appropriate pH is essential for water balance, ensuring that it is neither too acidic nor too alkaline. A pH level that is too low can result in corrosive water, which can damage pool surfaces, equipment, and may also irritate the skin and eyes of swimmers. By adding soda ash, the carbonate ions increase the pH level, making the water more alkaline and helping to prevent these issues.

Other substances, such as calcium chloride, are typically utilized to raise calcium hardness, while hydrochloric acid is used to lower pH. Potassium bromide is primarily used as a sanitizer and algaecide rather than for pH adjustment. Therefore, soda ash is specifically suited for the purpose of raising pH in pool water.