Very good filter. I used to have 2 on my 55G before I got my canister. You will like it.
The only con is that occasionally the spraybar get's plugged and needs to be cleaned out, which is simple to do and can be done without unplugging the filter. Just be careful so you don't get water all over. It isn't strong enough to spray the water over the side of the filter when you pull the spraybar off, but might get a little splatter while doing it. Just take the locking ring off the spraybar, and pull the spraybar off. Then when reinstalling, make sure the holes are pointed the right direction and push it back on, and put the locking ring back on. Very simple.
Also, if too much crud builds up where the biowheels seat down into the filter housing, it could cause the wheels to stop spinning. Simple cure is use an old tooth brush, dip it in the tank, and clean out the v-shaped thing that holds the biowheels in place.
Other than that, all I have is positive comments about the filter. I used ceramic cylinders in the baskets provided. I put the baskets in the slots closest to the biowheel, and the pad in the back slot.
Finally, with a 55G, you might also want to add a powerhead on the opposite end of the tank, just so that it doesn't get stagnant on that end of the tank. That was my reason for having 2. I also got mine a couple years ago around Christmas on bigalsonline.com and only paid 39.95 each. Another reason for getting 2, lol. The lfs here sells them for 109.00 each. lol.
for my 55 gallon. It is a bio wheel it look pretty cool.
