AntiPhos 500 ml fresh water phosphate removal media, Aqualine Buschke. In the aquarium, excess phosphate results in over fertilization, leading to excessive algal growth. Antiphos rapidly absorbs phosphate. Antiphos is based on natural zeolite, which has been chemically changed so that it binds phosphate. When the material is saturated it should be removed, thus reducing and eventually eliminating the phosphate from the aquarium. 500 ml for 50 gallons freshwater.