I just started playing with the PaX-Bellum. It's only been set up a week. But if you are short on a room, it might be an option for you. Reviews of the unit have been very positive.
I'm currently trying a upflow in my sump.I just used a long airstone got a piece of plastic canvas roughed it up zip tied it to airstone and dropped it in the return section of my sump. Propped an old 9 watt pc light against glass.I had a old black plastic lid I put behind it to keep light focused on canvas.it seems to be working. I'll post pics later pretty simple setup and it was cheap as well