Aquaclear? No way. The biowheels are nearly unstoppable on a Emperor 280. Is this new or used? Make sure the spindle is seated in the purple u-shaped holders. Also, the wheel shouldn't drag at all. You wouldn't believe how much bioload a 280 can handle. When you put that wheel out in the open oxygen, the good bacteria function extremely well. A brand new wheel spins like mad if the spray bar is pointed at it. Sometimes the plastic ends get separated a little along the axle in shipping and so they drag.
Also, is there a lot of water coming out of the spillway? If not, then you might not have the parts all seated correctly.
I have 30+ bio wheel filters and a commerical bio wheel running my central system. They are absolutely wonderful. I will conceed that the older bio wheels (think penguin 300 or 330) had terrible problems with getting stopped after a couple weeks. They've completely solved that. The biggest problem I have with biowheels is malaysian trumpet snails breaking my impellers. That's rare and nothing that copper won't cure!