DescriptionMetal Free is a powerfully effective hot tub metal, stain, and scale preventer which clears up and inhibits formation of rusty (iron), green (copper), brown or black (other minerals), or cloudy precipitates in spa water. Helps prevent scale, corrosion, and metallic odor. Most discoloration is from metallic source water impurities or a result of low pH on metal heater parts and equipment. Use Metal Free periodically, and these problems are gone. Essential for well water. Powerfully effective Non-toxic formula 16 oz. bottle Product notes: 1 bottle treats 625 gallons. Compare to Leisure Time Metal Gon. Metal Free is guaranteed to equal or outperform similar stain and scale products. If using the Cleanwater Blue sanitizer system, use Cleanwater Purge instead of Metal Free.