100% all natural bentonite clay - naturally occurring hydrated aluminosillicate of sodium calcium magnesium and iron. Ideally suited for re-circulating Koi and garden ponds.  Enhances the production of enzymes in all living organisms, improves water quality, and removes toxins from pond water. Beneficial to fish: colors will be more vivid and the white brighter, increased appetite and vigor. Beneficial to fish: colors will be more vivid and the whites brighter, Increased appetite and vigor!  Beneficial to plants: improves the nutrition by adding minerals that are lacking in garden soils and improves disease-resistance of plants.  Dissolves well - can be added to pond water, fish food or potting soil.  A 6 pound box can treat a 5,000 gallon pond for up to 1 year.