And for my next crazy idea:
I was thinking about the possible need to fan the tubs, and a way to automate that particular task.
I have a small diaphragm pump that is pretty powerful. Made for pulling water up into a tube or something, to bridge aquariums together, so fish can swim up and over to another tank, etc. It can evacuate or pump air too, and is better than a normal small air pump.
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Anyway, where my head is going.. nm the neon balloons, lol.
Instead of using it to force air directly into the tubs, I could fix a balloon to the end of each air line, inside of it towards the top of the lid.
Put it on a digital infinite repeat cycle timer, and fill the balloons up with air, which would displace the air inside the tubs, but without actually introducing any air through the pump. It could push out the co2 towards the bottom of the tub through one way check valves, and then suck air back through more check valves that are filtered with micropore tape, or polyfill, or even plain holes..
Time it perfect so it cuts off the flow to the balloons, without popping them (kinda like a flood and and drain), so the air comes back through when it shuts off.
The mono tubs could breath over and over, like they have lungs!