I think he means increase.It depends, how much ventilation do you have? If air is moving quickly through the space then C02 wont have an effect, if not, then I would say you would need one bottle per plant in an area that big to really have an effect. Honestly I dont think its worth the trouble, you are gonna put alot of work into something that isnt gonna help a whole lot. If you wanna decrease yield I would concentrate on lighting and good ventilation. But thats just my opinion.
cheers.
Lol, Sorry, im so baked i 4got to post the link
https://www.rollitup.org/do-yourself/180485-make-some-wine-c02-same.html