Well, after a solid 10 days of running with the new maxi-jet 1200, NO
microbubles are getting into the tank, and I've never seen such dark skimmate! It used to be dark with the Rio, but nothing like 'black coffee', which is exactly what it looks like now!
*update April 2nd*
woke up and couldn't hear the skimmer running. maxi-jet was fine, but the airline had built up some salt inside, and had stopped the airflow. rinsed it out and i'm back in action. I've heard of this happening to others, just never experienced it myself until now.