Sometimes (as in my case), regardless of how baffles are set up, micro bubbles can be an issue. In my case, it's tied to the amount of flow I'm running through the O/F.
The most common thought is to run a minimum of 3 baffles in a Down Up Down Pattern, approximately one inch apart. If you have the room and want to run sponges, space the baffles at two inch intervals. The theory behind D/U/D pattern is that you maintain a contant water height on skimmer side of sump.
Try and keep your return as far from the baffles and the direction of the mircro bubbles as possible in order to allow the greatest potential for bubble loss through surface contact.
If all that won't work, be a sissy like me and run a filter bag on your O/F and skimmer return.
We'd still like a see a pic of what your set up like, currently.