Highest porosity and largest useable surface area, per unit weight or volume, of all filtration media available anywhere. For use in all soft or hard freshwater or brackish aquariums. May also be used in marine systems. Provides huge amounts of aerobic and anaerobic surface area for efficient bacterial colonization. When properly colonized, and used as directed, it will reduce toxic ammonia and nitrites to near zero in all marine aquariums. Also reduces phosphate significantly and dissolved organics. Works excellently as the only filtration medium for the aquarium or pond or may be employed in addition to other filtration media.