SeaKlear Metal Stain Remover, 2lb container Made in the United States All metal stain removers Works on all surfaces including vinyl and fiberglass Removes metal and organic stains All metal, citric acid stain treatment solution Can be used in vinyl and fiberglass pools Effectively removes tannin, organic, copper, iron and manganese stains from pool surfaces Phosphate-free formula Before using stain treatment solution, make sure the pool is properly balanced