Not a big fan of my CF-500. I'm using it in not exactly the intended circumstances but I found the pump (both the manual priming pump which hasn't worked AT ALL and the actual electric one that runs the filter) to be crap.
Ended up spending more than the original cost of the filter to attach another pump to it externally, so it's basically a plastic tub with a weak UV in it now.
I love this filter. I'm getting another one once I get this weeks pay check. I have one 500 on my 125 and keeps my water crystal clear. It's just I've always like about triple the filtration needed for my tanks ha.