When was the last time you rinsed your filter cartridge? It needs to be done in tank water remove during a water change this is very important!!!. I use the overflow around the lift tube as an indicator that my filter pad need to be rinsed. If water is diverting down those lift tube over spills It means the filter pad is clogged and isn't letting water threw. Take about a gal
of water out of your tank and put the filter in and scrub it with your fingers while dunking it. WARNING: it will not be pleasant but its vital to your filter working correctly and a heathy tank. Once more water is flowing thru your filter it should spin your bio wheel more.