KDF-85 Process media is most effective in removing iron and hydrogen sulfide from water. Patented KDF process media are 100% recyclable and contain no chemical additives. KDF media is used to help safely reduce or remove chlorine, iron, hydrogen sulfide, heavy metals and bacteria from water. KDF 85 is used to add to an existing filter tank. You can add this to any other types of filter media such as a water softener or carbon tank to remove higher levels of sulfur, bacteria, or iron. You can add a few pounds or a whole drum depending on levels of iron and sulfur you are treating. Or is excellent for adding to refillable filter cartridges to treat iron and sulfur.