I'm running a CPR 3000 wet/dry with a 1500 GPH pump. Probably a bit of a overkill, it barely fits in the stand. The bottom of the tank is 8 inches from the top of the wet/dry. There is just barely room for plumbing and changing filter pads. I'm also running a 24 hour drip, so the only time I do water changes is when I drop the water level to vacum the gravel. I also have a Magnum 350 plumbed to the tank, that I used for awhile for water polishing. I found that if I used two layers of filter pads in the wet/dry (top layer light and the bottom heavy) the water stays really clear without the magnum.