Don't open it all the way. That won't give you maximum bubbles in the chamber. You want to open it just enough to fill the entire chamber with bubbles. The bubbles should be so thick that you can't see through it.
Look at the pics I posted above.
You are probably using the black tube that came with the powerhead. I would suggest replacing it with a piece of standard clear airline tubing. That way you can see through it. The air intake tube will get clogged with salt creep every couple days. It really screws up the bubbles because the tube is restricted. These things are VERY touchy. You need to have the little screw adjusted just perfect to get maximum bubbles and maximum skimming out of the unit. Keeping the air intake tube clear of salt creep really is mandatory. With the black tube, you can't see through it and you won't know when it's getting clogged with salt creep.
To clean it:
Just take the air intake screw all the way out and fill your turkey baster with some fresh RO water. Insert the turkey baster into the air intake tube and let the water flow through it. That will wash the salt creep out of the tube.
Now you will need to adjust it again. On my unit the screw works best about 1/2 turn from all the way closed. They are extremely sensitive. 1/32 turn too far open, and you will get a blast of bubbles from the black powerhead tube, but not enough to really fill the entire chamber with bubbles. Too far in, and you are loosing efficiency because there aren't enough bubbles to really produce any skimmmate. Take the time to adjust it. It really works great, but don't rush it and make TINY TINY TINY adjustments. You should be able to get that entire chamber completely full of bubbles. That will give you the best skimming efficiency.
The way you have it now is working for you because you don't want the microbubbles in the main display tank. TRUST ME--the unit takes a few days, or even a week to break in completely. Once it breaks in the bubbles in the tank will disappear. The unit will get more efficient as a coating of slime builds up on it and you will see minimal bubbles passing into the tank.
They still take maintenance almost every 2 or 3 days if you REALLY want it to work good. It's not something you can just adjust once and let it run for a month without messing with it.