Deep Blue Professional ADB41021 Ammonia Reducer in Jar with Media Bag, 35-Ounce Laboratory grade zeolite is an essential filtration additive used in aquatic fish keeping Safely reduces harmful levels of ammonia and other nitrogenous compounds The large surface area on zeolite granules promotes colonization of beneficial bacteria essential to a healthy aquatic environment Safe for both freshwater and marine aquariums Available in 35-ounce jar with media bag