3 in 1 design makes it ideal for gravel cleaning, sludge extracting and water changing. With the pump installed close to the end allows you to clean the tanks with lower water leavel compared with other cleaners. A strong pump easily removes particles from topmost layer of substrate without disturbing the bottom layer of gravel. It decreases the harmful toxins in your tank while reducing strain to your filter. The filter design straps the dirt while the water is returned back to the tank.