I am using two types on mine. One Marineland 350 bio-wheel, and one Whisper 60. I prefure the Marineland one b/c it is much more quiter than the Whisper, and it also seems to be moving more water.
well, I have about all of those depending on the tank. sponge filters for fry or breeding tanks, HOB power filters on my community tanks and some other species tanks, a canister filter on one community tank, internal power filters and powerheads with pre-filters for fish that like currents. I also have a bio-wheel pro that uses a sponge on a powerhead and runs bio-wheels. KYle