They do come in a variety of colors BTW.
The 90 degree angle gets around the poorly designed commercial designed that ripped off my original idea. Some poorer designs require a sponge at the end. Those blast off and lose too much gas and are unsightly. The venturi loop always messed with others and few understood it so many never added it, another poor design mistake.
That's what happens when someone copies your stuff, but does not understands it. So I show folks the better designed and nice looking DIY model and folks can make it for 1/5th the cost
Now if you keep adding more CO2, too much etc, the excess gas will burp out the hole opposite the pump and venturi side, so you have 3 ways of expelling gas from this unit/design.
1. Initially 100% dissolution
2. CO2 Mist
3. Burping slef regulation if you add too much
You never have to stop the flow gas(eg good for non solenoid user and DIY yeast folks) either. Simply turn off the powerhead to stop diffusion, the excess gas will burp out the top through the "burp" hole.
If you louse it up making it, the viewtainer is only 1.99$, so you can make another easily.
The venturi loop self regulates the CO2 level inside the reactor.
The efficacy is 100% until the gas builds up to this level, then the venturi suction from the powerhead's suction side starts pulling the gas in through the impeller and chops it up even further(2x , once in the venturi pull and then again through the impeller). The mist is gently expelled out the bottom in a downward flow and around the tank much like a diffuser disc except the mist is going down, not up and there's active flow out of the reactor.
This is also a self leveling device and bleches out any gas buld up in the reactor.
I think some copy cats thought the venturi was a bad since it appears to waste CO2, but that is not entirely true, the venturi is an advantage, not a detraction, you should have a fair amount of CO2 and be able to regulate it with a reactor, this one does that automatically for the most part if you use DIY yeast CO2.
A Rio 180 will run about a 40 gal tank, a 4x2 viewtainer is about all you need, longer and larger does not work as well as 2 such small units on either sides of the tank.
You'll also note ADA suggest multiple diffusers on larger tanks, rather than one big monster diffuser. Makes CO2 diffuser much more even this way rather than around a single point source. 4x2 reactors are easy to hide also.