Reverse under gravel filter

Reverse Under Gravel Filter: This variant of an under gravel filter runs in the opposite direction, pushing water up through the gravel. It requires water pumps of some sort to run, but needs cleaning less often.

Reverse Under Gravel Filter - This filter runs opposite to a normal under gravel filter where it pushes water up thru the gravel bed. This requires less of a filter cleaning effort relying on bacterial action to reduce the toxins.

TIA Thanks In Advance UGF, RUGF Undergravel Filter, Reverse Under Gravel Filter. WD, W/D Wet/Dry Filter WTB Wanted To Buy.

Solution - reverse under gravel filter. I don't know if you are familiar with these - reverse UG's take water that has already passed though a good mechanical filter (like the output of a cannister filter), and pump this water under the UG plate.

See also: Filtration, Under gravel filter, Filter, Fish, Gravel