KASS Koi Pond Bottom DrainThe KASS Koi Pond Bottom Drain is designed to remove fish waste and debris from your pond. It incorporates an air diffuser on top of the cover to aerate the pond and to produce a current that helps push the debris into the bottom drain. A KASS Koi Pond Bottom Drain is a must have for any serious koi enthusiast. Not only does it help to improve water quality by removing debris and waste, but it also ensures that the pond remains cleaner and healthier