I ordered a Marineland 400 HOB motor, housing and intake tube from ebay. I just need something to increase the water flow and as mechanical filtration to replace my 25 year old Marineland 280 (I think - it's so old I don't remember for sure what model it is) and the 400 takes the same E sized clamshell media cartridges as the old filter. I ran a bead of black silicon down the slots where the biowheel housing goes so all the water will be directed into the floss I'll fill the cartridges with. A new Marineland 400 costs $60, even including the cost of the small tube of black silicon I spent $20