Fluval Zeo-Carb is a premium blend of research grade Fluval Carbon and Fluval Ammonia Remover. Working together these highly effective media eliminate liquefied impurities odors and discoloration while simultaneously removing toxic ammonia for a clean healthy aquarium. Combining two products into one allows for more space within the filter for other types of media. For freshwater use only. For filter models: 106 206 306 406 FX5 105 205 305 405 104 204 304 404.