so if I am seeing right there is a bubbler there on the side and the gauges look like there is pressure.

Is there a valve on the bubbler that needs to open? seems there should be gas percolating through that, but why ? other than flow control? I have not seen any setup like that. most guys use biologics to produce low level co2 from above the canopy. or massive tank and sealed room jobs. Like to know how this works out.