Coral Essentials Reef ZeoliteCoral Essentials Reef Zeolite is naturally occurring, marine grade, zeolite rock, in a handy 2L bucket. Zeolite can absorb ammonia and other nitrogenous compounds and when used appropriately can quickly help reduce phosphate and nitrate in marine aquarium systems. It also has a micro porous structure which makes it a very suitable environment for anaerobic bacteria. It is best used in a reactor, or can be used in filter bags in the sump as close as