The water may drip from a spray bar or drip plate. The medium may be small pieces of plastic, DLS , or anything else which will support bacteria and not easily clog. UGF See under gravel filter . A device which uses UV light to kill bacteria and other tiny organisms. It consists of a perforated plate placed on the bottom of the aquarium and then covered in gravel.
Water is pulled through the gravel, under the plate, and up through lift tubes.
A type of valve which produces bubbles by drawing air into quickly flowing water. It is sometimes used on protein skimmers . A device which switches powerheads on and off at timed or random intervals, to simulate wave action in an aquarium. This is a form of biological filtration which has media exposed to the air to aid in nitrification. It is only effective in fresh water.