Orthophosphate is a commonly used corrosion inhibitor that is added to finished drinking water. It works by forming a protective coat inside pipes in the distribution systems and in customer homes to prevent lead from leaching into drinking water. The other name is phosphoric acid, and it is used to control alkalinityacidity in foods and beverages. It is a vital parameter for boiler, cooling and process water treatment. This water testing kit is again based on colour comparison. This kit is available in both low and high ranges.