. It's next to impossible for an air bubble to go under water, and come up the other end w/o popping.
HTH.
Not really true. It depends on the power of the return pump as well. I know this because this is what happened to my sump. I can see that the bubbles goes through the trap and ended at the bottom of my return chamber due to the high turnover rate of my return pump.
Mike: If you do not want to have a fuge, then you must carefully plan your plumbing such that your skimmer can take most of the raw water from the intake and processed it. This will help with processing the watse before it break down into nitrate and phosphate. Also, going with Berlin style, you want to "cook" your
LR until it is clean first. Why not you update your drawing to include the new dimension of the fuge as well so we can have a better idea.