CO2 boosters in small grow tents: Is it worth it?

It's not cost-effective. It doesn't improve quality, just yield. But the increase in yield is not justified by the increase in cost. if you go with 'exhale bags' you are better off DIY'ing it and save a shit load of money. Yeast and sugar. Get 30-50lbs of sugar for a grow, lol. There are studies sthat can give you ideas of how much yeast and how much sugar to get to 1200-1300ppm relative to volume of space you are dealing with.. if your tent exusts, then you need to calculate for the entire room it is in, not the volume of air in the tent. don't need it at night, as the stomata are mostly closed. It can take an hour or two for yeast/sugar tor each target co2 ppm, so if possible get that process started automatically before the lights turn on. if you really understand the concepts you can actually achieve quite consistent co2 levels for 12-18hours of light per day. My 2 cents.. It's cheaper in the long-run just to buy a 2nd tent and scale up than to use co2 and try to get 20-30% more yield out of current size of garden. Since it doesn't impact quality, there's no loss doing this either. to make full use of co2, you need a tightly controled environment. Temps and RH% should be controlled and providing a consistent VPD. Gonna need to be warm and a bit higher in RH% than you expect, lol, which is definitely a concern indoors. e.g. in winter you may damage your house with condensation onwindows and such... end up growing mold around all your windows and worse.