No offense intended to Fish Buddy, but bio wheels are a lot of unjustified noisy hype, imo/e. A large HOB type filter with some sponge in it is sufficient for most tanks. For heavily stocked tanks, a canister is better, you can pack it with some biomedia like Eheim's excellent SubstratPro, and then sponge or floss or whatever. What you need to build a large colony, is a large suface area of media. Biowheels have a decent surface area, but nothing like you can get in a canister with appropriate bio media. For HOB, i think Aquaclears are the best, and they are almost as versatile as a canister, allowing you to customize the media in the filtration chamber, although the chamber of course holds a lot less media than a canister would.
