lookin' good mojo, still pulling ~41?
Phil- Mine took a couple days to be "broken in," but I would say a full week or two before I could fine tune it to a certain spot. The IN100 works best in 7"-8" of water in your sump. You'll get varied answers with your question because some of us have gen1s (me) and others have gen2s (the bubble plate in the gen2 is a little shorter), also - I'm sure not all of us have our sumps at the same water level. But to answer your question my bubbles start about a 1/4 to 1/2 inch above the water level in my sump (sump level at 8") - the next inch up is pretty turbulent. I wouldn't use that method to determine much if I were you though, as long as your water level is 7"-8" or close to it you should not have problems. Just keep the wedge pipe halfway closed/open for now (or whatever makes you not overflow into the collection cup). Monitor it for a couple days, and slowly (millimeters) start turning the wedge pipe closed until you start getting a foamhead at the top - or to your own preference of skimming.