Pushing the lever down was very hard, and I felt like I was going to break it. It eventually pushed all of the water through the tube, but now the water is just sitting in the unit, and it's not pulling water in or pushing water out.
Is it possible that the tank does not have enough water in it? I really don't have it submersed much at all. Here are some pictures:
Notice the lever on the filter is not down... that is as far as I could push it. I tried lifting it all the way back up and then plugging it in, but that doesn't work either.



