If it's the black plastic box with the screened top and the various filter media in it, I think I'd honestly go to the flower pot with the lava rocks. Those suckers clog and float like nobody's business and it is a fscking pain in the ass to keep them clean enough. The purpose is to do a very coarse filtration to get the really big stuff out, and then clean the flower pot out weekly.

Show me some pics, so I can see. However, I think that the next step is really the flower pot. Just a old black plastic thing cast off from a nursery.

Remember that when you finally hit a few hundred gallons of water in there, that this probably gets a LOT better.