AZOO Max Bio Ball contains beneficial bacteria and enzymes, effectively breaking down ammonia, nitrite and nitrate in the substrate and water. The Bio Ball breaks down slowly for building a stable bio bacteria colony in the gravel bed. The bacteria process starts when the bio ball enters the water. The Bio Ball is specially designed for shrimp and nano aquariums.Directions: Each ball treats 50-100 liters (13-26 gallons) of water. Use every 2 weeks. Put directly onto the gravel bed for use. After opening, properly seal the bag. Keep dry and store in a cool place.