High quality granulated active carbon. Eliminates undesirable chemical compounds in marine and freshwater aquariums. Carbon should be placed in flow filters in 100 ml for 100 l (27 US gal.) of water in marine aquarium or 200 l (54 US gal.)in freshwater aquarium. Recommended flow is maximum 500l/h through the media. Welcome to visit our store: Aquaforest Aquarium Studio - Unit 15, 8 Quay St., Auckland CBD