I current have two bio-wheel 200's on a 55 gallon tank. Lately I have been dreading water changes because when I turn off the filter and turn them back on one of them doesn't work. Its only after I pull up the motor and intake tube and put it back in and jiggle and other things that it finally starts to work instead of making a clunky vibration type sound. Anyone know whats wrong and more importantly what I can do to fix it?