Installed at the lowest point in your pond, bottom drains are ideally suited for removing detritus to waste or filter system. They can be used on pump-fed or gravity-fed systems and can also incorporate air diffusers which help create a mushroom type circulation system within the pond that pulls particles towards the bottom drain and away. Whereas a bottom drain is used to clear particles in the water, pond surface skimmers can be used to skim floating debris from the surface of the water.