Hydropure METALTRAP™ MT-50 50K gal Pool & Spa Filter never lets metals in your pool. Why just treat metals when you can trap them! Real solution for bad water! METALTRAP™ is a unique, patent-pending, water filtration technology designed to selectively filter out stain-causing metals found in water. Unfiltered water can damage finishes and equipment and cause discoloration and odors. METALTRAP™ is a combination of filtration media materials that work together to give you superior metal removal.