Overall it can be a pretty good skimmer, but consistency can be a problem. Here are some things I've learned over the years which will hopefully make it work better for you.
1. use a filter sock on your return - this helps remove larger particles in the water which otherwise reduce the foam head. Other skimmers may not have this problem. aqua-c does.
2. use an oversized pump (mag 7, etc...) - more pressure = more and smaller bubbles
3. keep your hands out of the tank - oils will kill the foam head for several hours
4. keep the water level in the skimmer very stable. this means keeping the sump level stable.
5. keep the neck and collection cup clean (clean every few days)
6. cut and stack two pieces of egg crate (offset) to act as a bubble diffuser at the bottom of the skimmer neck. There is actually a little lip at the bottom of the neck that they set right on - helps reduce water turbulence and maintain the foam head.
7. wedge a plastic screw/wall anchor (or similer object) in the injector to increase pressure and reduce volume. Basically you end up with 3 little jets instead of a big Y. You want these to shoot straight down (not out to the sides).
8. clean the air intake valve often to remove salt creep. I slowly squirt a turkey baster of tank water through the air intake once a week to remove any buildup.
9. if you are using an oversized pump, it is highly unlikely that you will be able to run the air valve completely open. It's easier to produce a head with smaller bubbles but you need enough air to eventually move that into the collection cup. Too much air and you'll either have too much turbulence and too large of bubbles to produce any head or it will constantly overflow. Not enough air and you'll end up with dirty neck and nothing in your collection cup. You've got to find the sweet spot somewhere in between.
I think that's about it for now...
As far as the output noise how do you have it setup? If it's just pouring into the sump try attaching a 90 degree pvc elbow and length of pipe so the output is submerged. then drill a small hole at the top of the elbow to prevent a siphon.
good luck :)
