This product helps prevent discoloration of pool water due to iron, calcium, manganese, copper and other metals and minerals which may be present in the water supply. This product is an excellent general purpose sequestrant which helps protect plumbing and pool walls from rust, stain and scale. It should be used for all pool openings and closings and throughout the season as needed. For initial filling of pool, if iron or other metallic contaminants are suspected, add one quart of Metal Free for each 10,000 gallons of pool water. Add Metal Free while the pool is being filled and before chlorine is added. To correct an existing colored water problem (due to the presence of minerals in the pool water), first close the pool to all swimmers. Leave the filter pump running. Stop chlorinating the pool and allow the chlorine level to drop to zero. Lower the pH of the pool water to 6.8 with pH Lower, lowering the pH will re-dissolve the metallic impurities. Add one quart of Metal Free per 10,000 gallons of water and allow the pool water to circulate overnight, or until the water is clear. Re-adjust the pH of the pool water between 7.2-7.8 with pH Rise. Begin normal chlorination and pool operation. Swimming may resume when chlorine residual is 1.0-3.0 ppm. To make up for loss of Metal Free due to backwashing and/or splash-out, add one quart of Metal Free for each 20,000 gallons of pool water, once each month.