Air bubbles should be rising out of the large vertical "riser" tube. Those bubbles are dragging water along with them out the top. More water is flowing into the filter to replace it. Sounds like you have a working filter. Congratulations. Tell us how it works for you.
It isn't working... nothing is coming out! I just thought that the air had to go out somewhere.
As there is nothing coming out of the filter, I dumped all of the airline and valves into water to see if I have a leak. I don't. Any idea what's happening? I have a 10 gallon tank and the pump is for 10 gallons, but the pump is about 4.5 feet below the tank. Is that a problem? I tried lifting the pump above the tank to see if that helped, but it didn't.