Aqua-Tech Activated Carbon Cleaner for Aquariums removes odor and discoloration from aquarium water. Use this activated carbon in all aquarium filters to keep your tank looking clear and clean. First place carbon in media container or mesh bag. Rinse carbon with tap water and then place media container in the aquarium filter. You can use this fish tank water cleaner in virtually all models of aquarium filters. This product is simple and effective plus it s safe to use. Activated carbon is also useful for home cleaning and deodorization.