
Nice, but not inexpensive....
How about this?
As comparison, this box in a household shop in HK. I placed it upside down, this is how I would use it as the top is slightly smaller surface than the bottom so that when the CO2 pocket grows the reactor capacity increases (you don't want the reactor capacity to decrease when the CO2 pocket grows, as this would give a positive feedback loop **).
Sturdy, and with these clamps impossible to open accidentally.
19.9 HK$ = 2.5 USD, just for comparison.
Note: Cheating a bit, as this is a small box when I was thinking about good solutions for 10-20 gallon tanks. But you won't go broke with a bigger box from the same shop.
** I care about this feedback loop as I prefer to use my reactor in overflow mode. This keeps my injection perfectly stable, not affected by any instabilities from my CO2 regulator. If I would want to reduce reactor capacity, CO2
ppm in the tank, my solution would be to put a small piece of floating styrofoam in the box, reducing the active CO2/water surface, so that I can adjust reactor power by 10% or so without relying on my regulator. I believe on the long term this will be accepted as a low cost solution for CO2 injection, uncomplicated, adjustable by as little as a few %, and giving the best stability in the tank.
Note: Don't want to derail your thread
@SingAlongWithTsing , it is probably better if I comment further on the reactor in the other thread. Apologise if I added too much here. You may just want to go with the now proven concept of the pvc pipe.