As far as i understood the explaination it's mainly the pressure drop in the tube behind the ventiry responsible for sucking in the co² mulecules into the water. So there is a co² bubble sucked into the venturi, the vortex shreds it the pressure drop sucks it in. Along teh way through the tubing it dissolves even more before it hits the outlet..
Than my assumption placing a venturi behind a simple inline difuser can only be very beneficial regarding dissolving the microbubble even further..
As seen in the video, it's not realy a microbubble that is shreded, i also see some rather large bubles beeing spit out. I guess it comes down the the starting bubble size.
And it also seems to work in a rather low flow system, in the diagram it was placed in a shunt line (By pass)
With partialy closing the main inline valve a portion of the flow will go over the venturi and a portion of the flow will go straight on. A also assume that the flow in teh main tube should be greater. Than the diffused Co² will hit a increasing flow again coming from the shunt, again a possitive effect on further dissolving.
This is simply how it is adviced and installed by poolbuilders as the most sufficient ph nutralizer for swiming pools with the use of co² and a ph controler.. Any other way will cost you more if not to much co².. I have a hunge it is such a same swimming pool diffuser they use in lisbon..
And in mini version this should be awfully simple to DIY.. Theoreticaly.. If the pump can handle it...