Absolutely crap for CO2 production for fish tanks as the reaction proceeds too fast and will be exhausted in an hour our two. You either use sugar and yeast, which lasts a lot longer (and is cheaper) but if you insist you can use citric acid and baking powder but must devise a way to dose the acid into the bicarbonate.
Here is a handy guide to both methods.
https://www.co2supermarket.co.uk/diy-co2-kit-setup-instructions-guide-6.html
I would certainly add a third "trap bottle" to catch escaping yeast/citric acid as many people here have accidentally wiped out their tanks when the "reactor" contents have accidentally got into the piping and into their tank. Remember one way valves everywhere to stop the tank syphoning back into your equipment it the pressure falls. More than one person has ended up with a flood when a bottle springs a leak and tank starts syphoning back into the equipment.
As you cannot turn the CO2 off I would either run an air stone at night, when CO2 is not needed to degas the CO2 or a solenoid valve to vent to the atmosphere during the night. Issue with solenoid valve it makes the fish room small of lemonade or fermenting yeast when it vents.
Someone placed the yeast reactors in a bucket of water to keep reaction rate constant as they found they got algae outbreaks in the winter when their yeast reactor was colder. Ran wonderfully for ages until the aquarium heater he used to heat a bucket of water containing the yeast reactors melted a hole in the bucket and emptied the bucket out onto the floor.
Also someone had an exploding yeast container, as you do actually have to run with decent pressure in order to achieve decent CO2 injection rate.
I have run fire extinguisher bottled CO2 for 8 years now and am so glad I did not even attempt to use either of the above two methods due to all the drawbacks.