Sodium bisulfate, or dry acid, is used to lower swimming pool water pH and often will decrease alkalinity somewhat.
What is Sodium Bisulfate for pool use?
Sodium bisulfate, also called dry acid, is an acid salt also known as sodium hydrogen sulfate. Produced as a dry (anhydrous), light-colored, grainy product, it can be easily shipped and stored safely, though it can also exist in hygroscopic solutions and in other acidic solutions. Sodium bisulfate is used to lower the pH in many different uses; in the food industry as a safe additive, to decrease the pH level in water, and as a cleaning aid.
Sodium bisulfate is able to decrease swimming pool water pH when water has become too alkaline. Unbalanced pool water with high pH may become cloudy and is at risk for producing water scale on pool surfaces and equipment. Alkalinity of the water may also decrease, so both pH and total alkalinity need to be tested before and after adding sodium bisulfate to the pool water.
- Wikipedia: “Sodium Bisulfate”, http://en.wikipedia.org/wiki/Sodium_bisulfate