To raise the pH of pool water, which substance should be added?

To raise the pH of pool water, sodium carbonate is an effective choice. Sodium carbonate, commonly known as soda ash, is specifically used in swimming pools to increase the pH level. When added to water, it dissociates to form sodium ions and carbonate ions, which react with hydrogen ions in the water, thereby increasing the pH.

Maintaining proper pH levels in pool water is essential, as it affects not only water quality and clarity but also the effectiveness of sanitizers, swimmer comfort, and the longevity of pool equipment. The ideal pH range for pool water is typically between 7.2 and 7.8, and using sodium carbonate allows for a controlled adjustment of pH levels without drastically impacting other water chemistry aspects.