All I know is that I so glad to hear your voice...I figured you were busy and I hated so much to bother you,but I near tears trying to fix it on my own. I did everything everyone said to try. The little hose was giving me trouble before. I wrapped it around a power head stem, I tucked it behind the box...it's possible that it sucked air and I didn't realize it. I attached the hose to a rock in both tanks now with a zip tie. I will most certainly keep an eye on it.
The problem with the skimmer is that I never found that "sweet" spot. I do get some foam and very little brown skim, then the bubbles drop down and a brown yuck developes deep inside. It's like thick poop you can scrape out.
I get that same poop on the top and side of the cup too, but I'm thinking it should all be in the cup, and not in the body of the skimmer. So I try and get the bubbles up into the cup and when I'm not looking it overflows.
The "sweet" thing is that it doesn't leak out and around my tank or send microbubbles ...so I'm not at all unhappy with it. I just wish I could get it to that sweet spot.