I am not familiar with that skimmer. Typically, excessive microbubbles occur when too much water is being pumped through the skimmer. A lower flow allows more time for bubbles to rise, and not be forced out of the skimmer. The other cause could be too many bubbles from the pump, but this is less likely.
So, try adjusting the flow. Otherwise, you can always make a DIY bubble trap on the outflow.
Wish I could provide more help.