I had the same problem as my return was more like 7-8 x the display tank water volume and have my baffels spaced out 1 inch appart. WHat I did to reduce the mico bubbles substantially was in the baffel side where the return is I bought a box (2 pads) of the fluval 404 filter pads and put them inside the 1 inch baffel and on the opposite side where my skimmer and line in from the tank baffel is I put 2 smaller bags of carbon and the rest of the filter pad and viola bit of carbon to the system and pretty much no more mocro bubbles
Good luck.
PS - check to make sure you dont have any air getting into your return lines that could be a major problem as well that would be easily fixed.
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Honda CRF100