LOL, not a debate, more of a discussion. I am not going to lie to you when I say that after this discussion with Tom, I started pulling out all my research and study books from college with a small ring of doubt of my own logic in my ears. Alas, my thoughts and explanation are still correct as described above, however, I do see where the Tom is not wrong either. Its more of a technicality. LOL.
And we all learned a little more about CO2, diffusing gas etc.
That's how these discussions should go forth.
I take this same approach if I am curious, go do a little home work and see.
Take a position(whether you really believe it or not, matters less) and see if you can argue the merits.
Often both ideas have merits/trade offs, neither is correct, the world is not quite black and white.
I think a cooler name would have been a Powered Venturi Recylcing CO2 Vortex Reactor. LOL.
I think some theif took my idea some years back, so I showed folks how to to DIY for 2$ and under cut their money making scheme(50$ for their's) and they did not even get some of the core ideas from it.
As far as for the powerheads, I think needle wheel or impeller atomized aertion might be a better term. There is a difference between water pressure anytime a force acts on the water, so there's some pressure diffence.
They use this same general idea to push those water accelerators that folks put on the ends of the return out flows:
The pressure difference causes the sorrounding water to be pulled through. This requires energy and higher pressure to do and is a bit like those wave high flow Korlina pumps or the sure flo modifications to maxi jets.
It's like a very wimpy venturi. You can really drive the venturi concept harder, or go very soft.
For our purposes, particularly ith DIY, very soft is good, for larger tanks with lots of CO2, the mazzei venturi works nicely.
I like to mist the CO2, then feed it into the pump's impeller. But that's more for gas tank CO2. Here, the DIY reactor/mister worsk very effectively and is self leveling, self degassing.