polisher

So I was noticing my sump was missing some of the "finer" debris in my 125. I am on vacation this week so I decided to spend some time messing around with a way to improve it..... Mag 18 pump to a 4" sch 40 PVC pipe.. Filled with course medium and finer filter media ... Down to a tee fro the out...

I am interested in getting either a basic Magnum 350 or a 250 convertible canister filter (with micron filter) to use as a water polisher. I thought I would see if anyone here has one they would like to sell, before I go out and buy one.