Fluval Zeocarb, Three 150 Grams Packs (Fluval A-1490) for all Hagen Fluval filtersTop or Middle Media BasketsFor freshwater use onlyFluval Zeo-Carb is a premium blend of Fluval Carbon and Fluval Ammonia Remover. Working together, these highly effective medias eliminate liquefied impurities, odors, and discoloration, while, at the same time, removing toxic ammonia for a clean, healthy aquarium.