BioGuard Balance Pak 100 is used to raise total alkalinity. Maintaining proper total alkalinity prevents pH from bouncing due to rain, bather load, and other chemical applications. Low alkalinity may also cause pool water to be corrosive to the metal and plastic with which it comes in contact. This product is proven to help prevent pool staining, plaster etching or liner wrinkling. The contents of Balance Pak 100 dissolve quickly when added directly to water.