Seachem De*nitrate removes nitrates, nitrites, ammonia, and organics from both fresh and marine water. The high porosity of De*nitrate supports the proliferation of both aerobic and anaerobic bacteria that further remove these toxic aquarium byproducts. Even when exhausted as an organic adsorbent, de*nitrate continues to be an excellent support for the biological filter and does not have to be removed. DIRECTIONS: For best results, De*nitrate should be placed to assure the flow of water through it, such as in a canister filter, chemical filtration module, or box filter. Flow rate should not exceed 200 L (50 gallons*) per hour. If higher flow rates are unavoidable, use Matrix or Pond Matrix. It is best to rinse off dust before use. Once de*nitrate has been in use for several days, nitrate concentrations should start to fall and level off gradually at a concentration of about 4-5 mg/L as nitrate. As long as nitrate concentrations remain under control, the product is not exhausted. Each 500 mL of de*nitrate treats about 100-200 L (25-50 gallons*), depending on initial nitrate concentration and the current biological load. Enough should be used to remove nitrate at a rate at least as fast as the rate of formation. If very high nitrates are initially present, they should be brought down to less than 20 mg/L with water changes.