is an extremely porous filtration medium designed to be used in all aquariums and aquatic systems for bio-filtration. It literally has the highest surface area of any filtration medium in the world, by far, yet it provides excellent flow characteristics! Each liter of Exxodus•BAC provides over 71,000 square feet of useable surface area, internally, for bacterial colonization, providing for nitrification and vast amounts of anaerobic or anoxic surface area to foster denitrification, as well. One brick provides about 100,000 square feet of useable surface area for bacterial colonization. Doped with real aragonite for pH control at bacterial sites. Exxodus•BAC will reduce the levels of toxic ammonia, nitrites and nitrates, as well as phosphates and organic pollutants in all aquaria. It may be used as your primary or only bacterial filtration medium. It works extremely well in systems of all sizes. It is particularly well suited to reef systems with live rock including FOWLR systems and will not foster problems that bio balls may. Use in an external biological filter of any type. Works well submerged, or under gravel or sand, or in a drip system. For best denitration, restrict water flow through material. For best nitrification increase water flow through the material. Use in aquarium keeping. For maximum results, should be used simultaneously with BacterClean•M (Marine) or F (freshwater), BacterGen•M (Marine) or F (Freshwater), or BacterGen•MD microbial cultures, as appropriate, to jump start and maintain the colonization process at elevated levels. However for immediate operation in a new aquariums the use of Prodibio's Start Up item number 282044064032 is the perfect option as it is live cultures and therefore works immediately and can be added directly to your aquarium. If the aquarium is already established then Prodibio's Biodigest item number 280240172958 is the perfect product to get the media instantly running as it is live cultures of bacteria. Directions and protocol. One Exxodus•BAC brick will provide nitriication for about 1,000 U.S. gallons, ( 3,800 L ) of aquarium volume. Rinse brick gently in purified tap water or aquarium water. Pre-seed the product by placing it in a plastic container, submerged in aquarium water, and adding the recommended dose for your aquarium size of the aforementioned bacterial products (BacterClean or BacterGen). Allow the product to remain in this soak for 12 to 24 hours, stirring gently occasionally or agitating the liquid by pouring out and back into the container, gently. Place the seeded Exxodus•BAC plate into system. Or for easier instant start up use the Prodibio products mention above which can be directly added to the aquarium. The use of a pre-filtration filter floss, sponge or other mechanical pre-filtration is recommended to prevent fouling in flow through applications. The brick can be laid in a sump in any position of steady flow or within an external filter. The filtration properties of this product offer an active solution to filtration for up to 50 years, For smaller quantities please see our other listings also for the nitrtate biological media and the phosphate removing media. Which all offer the great same power of filtration.