Envii Nitrate Klear &ndash; Pond and Aquarium Nitrate Remover with Nitrifying Bacteria Treatment &ndash; (Treats Up to 3,000 Gallons) Reduces nitrate levels in pond water and aquariums to keep fish safe and stop blanket weed from growing Improves fish's oxygen intake Reduces risk of fish disease such as brown-blood by controlling nitrate levels Works in temperatures as low as 8C and each tablet contains 100 billion bacteria 1 pouch containing 6 tablets is able to treat 3,000 gallons