Seachem de*Nitrate 1L (33.8 fl.oz). Is a high porosity filtration productfor the removal and control of waste product in marine and freshwater aquaria by anaerobic denitrification. It is a porous inorganic solid about 4mm in diameter. It can be used in canister filter at slow flow rates or even on the tank bottom as a 'live' substrate enhancer. It does not require a special denitrifying filter or special culture feedings. It is also helpful in controlling nitrite and ammonia. The surface area characteristics of De*nitrate are similar to Matrix, making Denitrate an effective support for the biological filter. Each Liter treats up to 400L (100 gallons). Marine and freshwater.