Haole
"Village Idiot"
I really think this will help Carlos. With the way your baffles are set up, the last wall should send the water flow and bubbles upward allowing them to disperse to the surface given that the water level is well above that last wall. Instead, your water level is lower than that wall causing the flow to go downward once again along with the bubbles with not much room to disperse which creates a greater chance for them to be drawn into your return pump.