I guess that you cleaned the intake stem, strainer and impeller really good. It doesn't take much gunk in them to stop the bio-wheels.
I went on vacation one time and found one of my bio-wheels not turning and dried out. I cleaned the gunk and then kept spinning the bio-wheel in the reverse direction until it was good and wet. It started spinning on its own then. It was a little sporatic at first but after a while, it was balanced and worked just fine.