What common chemical is used to lower pH in pool water?

Sodium bisulfate is commonly used to lower pH in pool water because it is an effective acid that directly targets and reduces the pH levels. When added to water, it dissociates to release hydrogen ions, which decrease the pH level. This is essential for maintaining proper water chemistry, which can affect everything from swimmer comfort to equipment longevity.

The other substances listed serve different purposes. Calcium carbonate is typically used to raise pH levels and increase water hardness, making it counterproductive for this application. Chlorine is primarily a sanitizer used to kill bacteria and control algae; it does not function in managing pH. Baking soda, while another common chemical in pool maintenance, is used to increase alkalinity and can also raise pH, rather than lower it. These distinctions highlight why sodium bisulfate is the appropriate choice for decreasing pH in pool water.