Eliminating DIY skimmer noises

[crn005]

So my build is pretty straight-forward. It's an air stone driven, external, counter current skimmer. It functions well but I'm just curious about how all of y'alls work. The cap I have over my return pipe has a small hole in it which eliminates all of the gurgling sound but the water going through the tube still makes a bit of noise.

My questions are:
1) Is this normal in other people's skimmers?
2) How can I improve the design to allow more air exchange in the return tube causing the noise to go away?
3) How can I eliminate some of the micro bubbles cause by the water in the return tube (when the water gurgles causing air to enter and then when those bubbles collide with the surface of the water)?

Here's a picture just incase you need a visual of my skimmer.

http://i1071.photobucket.com/albums/u502/crn005/0C12C8A0-2127-4839-B1AB-BDF269595BA8-10772-000013631A9CF4E7_zps4de9db88.jpg

[crn005]

Well, I guess I figured it out. I'm just going to have to move some things around in the sump to make room. That's the reason it didn't go in initially. Oh and I need to lower the exit pipe to under water level. Putting it inside the sump solves a lot of problems. It eliminates the gurgling, gives me piece of mind from leaky plumbing, and keeps my pump from pushing too much water through the chamber. I need about 22 gph to have the correct water to bubble reaction time.

I'm still open to suggestions though. Also, I'm still curious to hear about what kind of noise y'alls skimmers make. My design is very similar but for some reason, I guess y'alls don't make as much noise. Mine was simply just too loud.