I know this board probably isnt the best place to ask this, but I am dealing with a big system at the school in a multi-million dollar facility...... Lets just say it could have been designed better. I know the basic concept of skimmers, but not an expert, so I would like a little advice.

The protein skimmer I am dealing with isnt complex, its fed by either a danner 12 or 18, goes into a venturi and into the main lift pipe. The issue is the bubbles are not getting enough head, they look WAY to big to me, some of them are as big as 1/4-3/8" and it doesnt look like there is enough of them. I dont know if the pump is to weak for this setup, or it has a crappy venturi, or both, or something else entirely.

I have tried adjusting the air inlet, it is all the way up in these pics, but doesnt help nearly enough. Thoughts? Ideas? Options to get this working cheaply?