TwoLittleFishies HydroCarbon 2 G.A.C. is a granulated activated carbon designed specifically for the purification of water. It is manufactured by steam activation and acid washing of a special Lignite material under carefully controlled conditions to produce an activated carbon most suitable for aquariums. Since it is extremely porous and positively does not leach phosphates that can stimulate the growth of algae. It has a very low ash content and therefore hardly affects pH. HydroCarbon 2 G.A.C. has a wide range of pore sizes and large pore volume that provide a rapid adsorption rate plus a high capacity for dissolved organic compounds. It has the highest capacity for removing water-yellowing tannic and humic compounds of any commercial water activated carbon, and adsorbs both large and small molecular pollutants, including defensive substances released into the water by soft and stony corals. The macroporous structure of HydroCarbon 2 G.A.C. also affords a high ability to resist clogging that can interfere with the adsorption of dissolved organic substances. The granules are the optimum uniform size for use in high capacity filters, allowing even-flow of water at high velocity with minimal back pressure. HydroCarbon 2 G.A.C. has a long useful life. After months of use it also becomes a very active biological filtration community full of beneficial bacteria and microorganisms. It can thus be used as a biological nitrification, denitrification media, or to seed new aquariums with active bacteria cultures.