Super Erace is our best selling specialty in our family of problem solving products! Super Erace is a unique formulathat actually forms large crystalswith the metal ions in the pool water.These crystals are then removed by the filtration system. Most other mineral treatments temporarily hide the problem, while Super Erace actually eliminates the problem. Super Erace will remove metallic stains from all pool surfaces. Super Erace is compatible with most sanitizing systems. 1 quart treats 10,000 gallons of water for metals in solution, as detected through testing or 1 quart per 5000 gallons to remove metallic stains.