This is what I think I might do, is cut a piece of acrylic to fit snuggly in the filter slot, drill a bunch of holes in the bottom(of the acrylic),put some ceramic rings in the bottom in front of the acrylic, some filter floss on top and then a course sponge on top of that behind the grates. And then on the other side put some ehiem bio balls then put some purigen on top of that.
Heres a rough sketch:
Are you talking about sliding a piece of acrylic in the slot where the current cartridge goes?
What I did was pull that cartridge out. I drilled holes in the very bottom of the media chamber then clued a small piece of plastic over the slit on the right each. Then stuffed that entire chamber full of filter media. That way water has no choice but to be pulled through the filter media and out the bottom. I but a bunch of Bio balls in the second (big) chamber with the pump. If you decide that first chamber in half its going to reduce the size of your filter media. I drew you some pictures but can't upload them from work.
Last edited by HunterX; 10-26-2012 at 06:23 PM.