IOAOI PuriResin Aquarium Filter Media, Organic Filtration Resin, for Freshwater and Saltwater Fish Tank, Removes Driftwood Tannins, 100 ml, 5 PacksBrand: IOAOI Features: FUNCTION. This filter media is an organic filtration resin which is developed to remove nitrogenous compounds and waste produced by fish, corals, and even plants, making your water crystal clear. SPECIALTY. This special filtering material is not a mixture of ion exchangers or adsorbents, but a unique macro porous synthetic polymer that removes soluble and insoluble impurities from water. ADVANTAGE. Being both spherical and