Not sure if I’m allowed to link other forums here but here is the template I used to make mine with a slight modification :
https://barrreport.com/threads/dual-venturi-diy-external-co2-reactor.3413/
Check out my thread to see my reactor. For the bottom part I used a 90 degree elbow instead to sit better in the sump. I assume it’ll be just as beneficial in a cabinet.
Mind you, the recommended flow through the reactor is around 300gph, slow enough to allow proper co2 dissolution . Your canister looks big (GPH?)and might be too much for this size reactor so depending on the flow you might want to up the reactor size and fittings to match.
Let’s say as an example if your canister puts out real life numbers around 800gph, double the size of the reactor to 2ft instead of the 1 ft or slow down flow via the canister valves.
It’s a matter of flow and also the space available in the cabinet but it’s in my opinion one of if not the best co2 infusion method .
The drip irrigation valve on the Venturi is a must to remove gas build up and you can find them at your local hardware store. 1/4” valves work perfectly with the 3/8” co2 lines.