Here's how I set mine...no guarantees that this is correct though. Cut the air off all the way. Start opening it up until you get a tight swirl of air/water up the center tube. This should break up at the top and the fine bubbles should go at least 75% of the way down the outside tube. If the water movement almost stops and you are getting large bubbles, you have too much air. Mine is set so that water flow through the skimmer is cut about 50% from where it is with no air at all. You will get bubbles back into the tank with the SeaClone for quite a while. Mine has never completely quit doing that. The SeaClone isn't the best skimmer out there, but I have to admit that my puffer tank looks a lot better since I added one to it. Once it starts working...pulling skimate...I would clean the cup at least every other day. I hope I haven't made this more confusing than it was to start with.
BTW, I'm thinking a surface skimmer/return bubble trap would increase the efficiency of this skimmer a lot...probably have to
DIY it though. I wonder if the one for the Aqua C Remora would work?