I'll try to help you out. Let me predicate this by saying I haven't used Reef Octopus skimmers but most all work the same.
Where are you getting the micro bubbles? It's pretty difficult to see in the pictures...Or I'm missing something. Maybe the one picture
Where does the drain tube from the collection cup go? Looks like it circles around the base of the unit and back into the water! That's not the cause but would be putting the nasty stuff right back into your water. That needs to discharge outside the system
My guess on the bubbles is too much air flow into the skimmer. Can you restrict the air flow? Or shut the valve on the discharge a very little bit. Like maybe 1/8 of a turn, then wait for 15 minutes and see how the skimmer reacts.
New skimmers do tend to over produce