Abstract: A composition for treating water contained in enclosures, such as swimming pools, spas, whirlpool tubs and cooling towers, which includes at least one boron compound, cyanuric acid, at least one mineral remover and at least one clarifier is provided. A composition and method for treating salt water contained in enclosures using halogen generators to generate sterilizing halogen in situ, wherein the method includes adding to the water effective amounts of a composition having at least one boron compound, cyanuric acid, at least one mineral remover and at least one clarifier, such that they are present in the water simultaneously is also provided.