KDF 55 Filtration Media for Chlorine, Heavy Metal, Bacteria, Iron Removal (10 lb.) KDF 55 Process Media can remove up to 99% of water-soluble lead, mercury, nickel, chromium, and other dissolved metals. KDF 55 is used to add to an existing filter tank. KDF Process Media are high-purity copper-zinc granules that use redox (the exchange of electrons) to remove chlorine, hydrogen sulfide, water-soluble heavy metals and microorganisms from water.