SpaGuard’s Stain and Scale Control enable spa owners to prevent and remove stains caused by iron, copper and manganese, as well as scaling caused by a high level of calcium. Stain and Scale Control’s formula bonds to troublesome metal ions in your spa water and filtering them out, eliminating scale build-up that causes cloudy water and can clog up filters, and other metals that cause unsightly stains. Simply add this powerful liquid formula weekly to safeguard your spa or hot tub from these threats.