This is an excellent thread...STICKY!
I found this YouTube video to be extremely helpful...(NOT to advertise for this particular brand of sponge, though it is what I purchased):
It looked complicated before I bought it, but it's not. And mine actually came totally assembled. For use with an airstone, attach a 1/2 to 1 inch piece of airline below the bullseye assembly and attach a cylindrical airstone to it. Then attach the airline to the pump on the top side of the bullseye. (The top side connection is shown at 2:20 in the video.)
I mention a cylindrical airstone as that is what is most likely to fit. Hallyx and Callistra taught me how to connect mine when it came in!
I have one suggestion...could someone who has the capability include photos here of the different effects achieved with the lift tube cut at well under the water, at the surface, and above the surface? Some members have been trying to help me understand what the different heights will do. Mine is at surface currently and I'm thinking of cutting it down about an inch below. I was hoping to get a height that would keep the filter from "spitting" mist all over the underside of the lid. I might try the java moss suggestion if I can find some at my local store...Got to get the back-flow protector valve also...
I have a Tetra whisper airpump and it is super-quiet...
I'm a newbie at this, but if you're new, too, rest assured, it is MUCH easier than it looks. I should have bought this type first!!