Well, i made a few mistakes in setting up my refugium and decided it was time for a redu. First, my 125gl refugium sat on a shelf that i insisted upon using 4"x4" posts laterally instead, as everyone suggested, using 2"x6" or 2"x8"s. Turns out everyone else (including a thread here on RC) was right, as the 4"x4"s warped a bit, enough to leave a 1/8" gap between plywood base and acrylic tank in the middle. My error was further compounded by not using styrafoam underneath the tank which would have compensated some. I cut out the styro so my gravity drain feed to the refuguim had enough slope.