UNS 5N Plumbing CO2 Reactor

I finally completed the plumbing for my UNS 5N. I usually do what everyone else does, and install the CO2 reactor after the filter, but this time, I installed the reactor before the filter so that it would have negative pressure. In other words, the filter’s water pump will be sucking CO2 out instead of installing it after the filter, which will be pushing water into the CO2 equipment. When the CO2 system is on, it has enough pressure to push the CO2 into the plumbing, but when it's off, if the check valve fails, you'll find water inside the CO2 system. In theory, I wouldn't need a check valve, because of the negative pressure. My reactor is large enough so that the CO2 dissolved 100% before it even enters the filter.

So far, I have not heard any air enter my Finnex PX-360 canister filter, which leads me to believe that there will be no damage to the filter's impeller.

I doubt that the pH would be low enough to kill them off because the water entering from the aquarium has CO2 as well.

It’s not worth my time to modify and install some kind of device that measures the pH inside the filter and inside the reactor.

Don't expect this aquarium to be a beautiful aquascape anytime soon. I just threw in some random plants and fish. I'm focused on my 120U at the moment. This video is mainly about the plumbing.