I've been doing the tango so long with the case my wife is getting jealous

But seriously, I think the issue may be the water level + there seems to be a micro vortex happening in the res. I see the bubbles come in and then they spin around but never go over the separating plate before they get sucked back in the 'out' hose.

I'm thinking of lowering the water level so perhaps the bubbles just filter out when they hit a half empty res. . .