* Chemical filter media scientifically proven to reduce phosphate and silicate * Effectively removes phosphate to help reduce aquarium maintenance caused by excess phosphate * Provides long-lasting phosphate control in fresh or saltwater aquariums Aquarium PharmaceuticalsA specialized, synthetic adsorption filtration media that selectively removes phosphate in fresh and saltwater aquariums, as well as silicate found in tap water. Phos-Zorb effectively removes phosphate and silicate and will not release them back into the water for long-lasting phosphate control. A clean aquarium environment free of excess phosphate means enhanced growth of corals in saltwater aquariums and superior plant growth in freshwater aquariums. Phos-Zorb also helps prevent calcium precipitation caused by excess phosphate in reef aquariums to help promote the growth of reef-building corals. Effective for up to 8 weeks. Safe for all fish, invertebrates, and plants. Net weight 5.25 oz in mesh bag. Treats up to 55 gallons.