Dr. Tim's Aquatics Waste-Away Natural Aquarium Cleaner for Reef Aquariums helps keep your aquarium clean with crystal-clear water. Using novel， sludge-busting， beneficial bacteria， it naturally dissolves sludge and dirt that accumulates in an aquarium and prevents the build-up of waste when used on a regular， weekly basis. Waste-Away is fast acting and specially formulated to remove aquarium gunk， unclog gravel and coral beds， and keep filter pads freely flowing longer. This results in better water flow， more oxygen， and a healthier aquarium environment.