I also have a Seaclone skimmer. Mine works really good. I have to empty the cup usually daily. What I have found are a couple things:
First, if it is brand new it will require a couple of weeks to "break in"...so you will see the bubbles for a while. It only took 3 days for mine to stop producing bubbles.
Next, make sure you are getting clean air from the tube. Adjust the fitting on the tube to 1-1/2 full turns and let it go. That seems to be the best setting for the SeaClone skimmer. It will start producing "coffee" within a few days of break-in provided you have something in the water to skim. You just have to be patient with any skimmer. They just don't start working right away.
Also, I never adjust mine after the initial setup. You just have to make sure that the air line is where it will get fresh air as opposed to salt laden air. The salt air will eventually develope salt creep into the hose and clog it and then you will have to clean out the hose to make it work correctly again.
Also remember that when you "clean" you skimmer, it will have to "break-in" all over again. I clean mine every 3-4 months.
From all of the bad posts that this skimmer gets, I must have been so lucky to get the ONE that actually works...LOL
Anyway, I hope this will help you out some.
125 Gal-35 Gal Wet/Dry-Tetra-Tec PF500 HOB
(3) AuquaClear 301 Powerheads-600 GPH
Automatic Tempature Controller
5-6 Inch Sand Bed-200+ lbs of LR