I have that skimmer, and it took several days to get going. leave everything wide open as long as the water level inside the box is at an appropriate height (per the instructions)
If it's low, then you'll need to close down the gate valve a bit to raise it up, if too high, tune down the pump just a bit.
Leave the air wide open until you start to see foam generated.
The bubbles are a lot worse when it's not broken in, as the foam starts to get going, the bubbles in the output seem to reduce.
I'm running mine with the Dolphin DP-560 pump and running it external to my sump.