Use 1 cup per 20 gallons, more can be used for greater effectiveness Replace every 3 to 6 months or as needed.
Kent Marine Nitrate Sponge is a granular zeolitic medium which works by two methods:
By slowly adsorbing the small amounts of ammonia that is releaved by fish and other natural aquarium processes.
The Spong fosters anaerobic bacterial denitrification beacuse of the sponges porousness.
Denitrification slowly reduces nitrate levels in your aquarium. Working well in either freshwater aquarium tanks or tap water to remove the toxic ammonia. The Nitrate Sponge lengthens the time needed in between water changes, and should be used with a mesh bag to contain the sponge media.