Powerful Formula: Natural Chemistry Spa Metal Free targets staining and discoloration from trace metals including iron and copper, by using a very efficient metal chelating agent. Phosphate-Free: Unlike other stain and scale products, the Spa Metal Free chemical will not raise phosphate levels. This product should be used as part of a spa maintenance program. Protects from Staining & Scale Buildup: Spa Metal Free helps protect against surface staining and water discoloration caused by metals in pool water and protects against calcium and mineral scale buildup. Compatibility: This product can be used with most sanitizing systems and is compatible with all spa surfaces. Do not use with biguanides. Tested and Proven Effective: Natural Chemistry products are known for delivering reliable results and making water care less complex. Natural Chemistry carries an extensive line of pool and spa solutions that match your unique needs. Natural Chemistry Spa Metal Free targets the staining and discoloration of trace metals including iron and copper, by using a highly efficient metal chelating agent. Unlike other blemish and flake products, Spa Metal Free Chemical will not raise phosphate levels. This product should be used as part of a spa maintenance program.