lilbuddy -
I don't prefilter (past the sponge) right now... but I think I'm going to use a micron sack.
I jsut have 2 x AquaSun's, I used twin tube lights that came with the tank that I didn't need anymore when I upgraded to VHO above.
But you can buy small PC's that are used for sump/plenium/refuge type applications.
-Scott