Is the wheels suppose to spin at all times? Mine don't it spins some times but not constant.
the wheel should be spinning at least a little all the time
It's normal for it to not spin constantly over time. In fact Marineland says that's a good thing!! The only problem is if it stops spinning entirely. If that happens, the filter probably needs a good cleaning and that usually gets it going again. If you decide to clean it, don't let the bio-wheel dry out and don't let it make contact with tap water. That is where the beneficial bacteria resides. Which is also why you never want it to completely stop spinning.