Removes fish waste and other muck that accumulates on the bottom of the pond. Ponds over 2.5' deep can become stagnant on the bottom. A bottom drain will suck the debris from the bottom of the pond and send it out of the pond in to a designated drain line. This bottom drain is plumbed underneath the liner for a nice clean look so no pipes are visible. Adding a bottom drain to a pond will keep maintenance lighter for the homeowner.