Bubble magnus tuning issues

[S2G]

It's a curve 9. This thing is a royal pain to work properly. It's been months and i still cant get it dialed in to work halfway decent. I've adjusted the water level, cleaned the air piping, made small increment changes, and still overflow or under flow. I run the clean white bubbles about halfway up the where the collection cup is, but it fluctuates like crazy. What am I missing here?

Maybe there's nothing to skim
180
Stock:
8" foxface, 5" scopas tank, full grown percula, 16" snowflake eel, 3 cardinal fish, 2 damsels, and 1 big baseball size urchin

 

[reef lover]

When i ran that i kept it down below the cup that way when it did go nuts it didnt overflow...eventually replaced the unit.