Description: Biofiltration Substrate for Refugiums, Mud Filters, All Marine Aquariums, and Seagrass Beds. What is Marine Biosediment? Kent Marine Biosediment is a blend of aragonite, calcite, and other minerals; it is not any mere aragonite substrate. Marine Biosediment has been formulated in ratios that not only provide a much more natural substrate composition and density than using plain aragonite alone, but also to slowly dissolve as a result of natural solubility and close-proximity bacterial respiration, simulating the processes at work in sediment found on reefs, in lagoons and sea grass beds, and around mangroves. Rather than being a blend of terrigenous (terrestrial in initial origin, i.e. silica sand, humus, etc.) particles, Marine Biosediment is composed of minerals naturally occurring in the afore-mentioned marine habitats, and therefore brings the aspiring hobbyist one step closer to providing his/her aquarium inhabitants a truly representative piece of the ocean. Over time, Marine Biosediment slowly releases trace amounts of calcium and other elements due to microbial processes taking place below the surface of the substrate; again, this simulates natural cycles taking place in benthic marine ecosystems. To calculate the number of pounds of Marine Biosediment needed to obtain a particular sediment depth in a refugium, follow this formula: (Refugium L (in.) x Refugium W (in.) x Desired Depth of Marine Biosediment (in.)) x 0.05 = # lbs. Biosediment needed Directions: Read Use and Interaction on opposite label. Employ about 5 pounds of Marine Biosediment for every 25 gallons of actual water volume in the entire system. For use in refugiums and mud filters (recommended), the depth of the Biosediment should be 3–4" for optimal denitrification; in display aquariums in which Marine Biosediment is the sole substrate, it’s not recommended that the depth of the Biosediment exceed 2". It is recommended that this product be placed in dry, clean aquariums or refugiums before water is added to avoid unnecessary turbidity. Slowly add water to the desired height, then anchor algae in place; allow 2-3 hours for any cloudiness to clear up before turning on pumps. Caution! Not for human consumption. Keep out of reach of children! *HEAVY ITEM* - Price includes $3.00 of additional shipping fee!