I have a reef octopus also. After checking to make sure I have the proper water level, all connections good, that the skimmer is seated properly, etc., it will take a few weeks to break in and the micro bubbles will work themselves out 95%. I freaked out a little bit cuz i read somewhere that micro bubbles kill fish. I had bubbles for a few days. No casualties.
It took me several hours and patience to dial mine in. I would make a very small adjustments to the tube and wait 30 min to see how that little adjustment will affect the skimmer (this is why it took so long). I would keep an eye on it and see if it started overflowing, then obviously i would dial it back, but most of the waiting for me was to get it to where the bubbles would start getting close to the overflow cup and waiting as they build on one another and get higher and higher on their own. Also, don't do anything immediately after feeding. Feeding changes the dynamics of my skimmer for a few minutes immediately after. I also added carbon for a few days and pulled it out because it also threw off my skimmer. This was just my experience. Good luck.