Funny, I was just contemplating this today. I have a central system running and it occurred to me that even though the sump acts as a giant filter there's really nothing "filtering" the actual tanks. Its basically all gravity. Pumps to the top and drains to the bottom but what actually is being filtered? At least with a cannister like the FX5 which is very large, i think I could some how make filter intakes into each tank with pvc plumbing of the FX 5 input line.(using 3/4 " pvc with ac 110 extra filter extensions since they fit or just order some bulk head strainers etc.) Then let the gravity flow to the drain to the bottom as normal but into the input line as well with a ' T ' fitting. Well actually a whole bunch of ' T ' fittings.And of course the output would go up in 1 straight line into a ' T ' that would drape over the back of the 2 top tanks and let the process start all over.