First One

Short answer: in a normal tent with an exhaust fan running, no. the fan pulls the co2 out almost as fast as any kit can make it, which matches what tjaym saw. Rough numbers for a 4x4 tent held at 1,200 ppm with about 112 cfm of exhaust: you lose around 265 g of co2 an hour, while the plants only take up about 6. So only 1 to 2% ever reaches a leaf. Yeast kits and mushroom bags make a tiny fraction of that, and even a tank runs dry in a day or two of lights-on. Where co2 does pay is a sealed room with its own ac and dehumidifier, at 800 to 1,200 ppm, lights-on only, with a co2 meter like 00110001001001111O said. For a vented tent the useful co2 move is the opposite: keep the exhaust running during lights-on so the plants don't pull the tent below room air. a sealed tent can drop under 200 ppm in about 20 minutes.

Will depend heavily on volume of air and how well the area is sealed. For reference, you need 30-40lbs of sugar to feed yeast to produce enough co2 in a small room for the duration of flower.... if it's a 'kit' relying on yeast... you need a co2 meter anyway for safety.. .either it reaces 1200-1300ppm or it does not. A large volume of air will need significantly more co2 than a small volume of air.. insufficient information. most likely not as others said.

Der Mehrwert ist gering verglichen zu der Masse die potenziell mehr geerntet werden kann. Ich würde es nicht empfehlen…