I've got 4 plates connected in this same fashion on my 100 gal tank. The area under the plates stays pretty clean. I have a single Magnum 350 pull through the plates, and a another Magnum 350 performing water polishing duty.
I don't like the way that guy did it on e-bay, but only for aesthetic reasons. His PVC piping manifold sticks up noticeably and doesn't look all that great, though I am sure it is a very functional setup.
Built my setup by first milling down all of the gravel guards on my plates, and then capping them with the supplied plugs (Lee Premium UG Filter Plates). I just used my tablesaw and rip fence...this may seem like overkill, but it beat using a Dremel, and it all went quickly.
Had to leave one riser port open on each plate, milling these down to the minimum as well, then used a small piece of riser tube to insert into each port and then into a 3/4" elbow or tee as appropriate. The Lee thinwall tubing is not a perfect match unless you push it in almost excessively into each PVC fitting...I had to "fishmouth" a portion of each tube to ensure adequate flow area into the main manifold from each plate.
I wish I'd taken a digital photo of this effort, because all of the piping is now neatly hidden under a bed of gravel (except for one fitting that sticks out to take a 3/4" black vinyl tube that slips nicely over the inlet downpipe of the Magnum filter). As long as I keep the feeding amounts reasonable, the gravel cleaning is a non-issue. The Magnum 350 pleated cartridge for the UGF does need changing more often than the one on the other Magnum, but that's expected. Then again, it's tough to keep feeding amounts "reasonable" w/ over 120 guppies (I just sold 75+ of them...they just won't stop reproducing!!!).
In short, pulling through the gravel works. Whenever I do a water change, I vaccuum gravel (same as on my other tanks). I put in a large Amazon sword, and it is thriving. I'm putting in some Val and Sagittaria this week.
v/r, N-A
