Definition: Gravel cleaners are siphon driven tubes that are designed to draw water and accumulated wastes from beneath the substrate. This is a vital maintenance technique for ensuring the gravel is kept as free of wastes as possible. As the rigid tube is drawn through the gravel, the suction from the siphon draws some of the gravel up and into the tube, this speed of the siphon should be such that the gravel easily falls back down but the dirt and debris is light enough to be carried up and out the tank and into the bucket.