I find that the large air valve on my EV-240 is very sensitive. So, I inserted a small length of hard tubing into the small opening provided for ozone and/or calcium effluent and put a small air valve on the end of the tube. I use this for a more fine air flow control. I'll post a pic once I get home. Not all models of Aqua-C have this additional opening.
I suggest running the skimmer pretty wide open, and just let the effluent run back into the system for a couple days. This will allow a film to develop and help to break the skimmer in. Then, route the effluent out of the system, but tune the air input/bubbles down so that your not capturing any output. Then, make tiny adjustments daily to the air input and overall water level using the supplied gate valve, until you are producing skimmate. Then, don't touch it.
My experience is that certain things will cause the foaming to increase, or decrease altogether - like cleaning, or feeding. I think it's important not to chase these reactions by making adjustments to the reactor, because when things return to their "normal" state, you'll either be producing too much, or not enough skimmate. I have mine adjusted to produce as dark and thick of a skimmate as possible. I also find that my sump water level affects skimmer performance as well, and that I must maintain the water level on-center with the gate valve output.
Hope this helps. I have nothing to compare it to, but think the Aqua-C skimmers rock.