Aqua Natural Shadow Bio-Substrate Aquarium Gravels are 100 percent natural, for any aquarium including planted tanks. Create natural beauty combined with large surface areas for beneficial bacteria colonies and easy cleaning. It is tasteless, odourless, dustless and sustainable. Contains bioactivated live nitrifying bacteria to either use as a primary substrate or mix with substrate for a healthy aquarium. Contains a patented blend of live nitrosomas and nitrobacter bacteria which break down and convert harmful ammonia, into nitrates. It can also be used in pot plants, fountains and candle holders, just about anywhere.