API POND AMMO-LOCK, 16 OZAPI POND AMMO LOCK ammonia detoxifier serves as a source of nutrition for good bacteria in your ponds natural biological filter. It also detoxifies poisonous ammonia, which is continually produced in your pond by waste, to a safe form for fish. This product eliminates ammonia stress, and promotes healthy gills and a safe pond environment for your pond fish. Add 0. 25 cup for each 250 gallons of pond water or 1 cup for each 960 gallons.