manualy feeding Co2??

So I was cleaning out a friends basement and we came across a CO2 tank that he used to use for his beer brewing days. The regulator is fucked. Now my question is, can I jus shut my fans off for a bit and blast them with some out it? I don't have $ rite now to buy a Co2 timer kit and such. Its a smaller tank like fire extinguster size. If I get a regulator kit thingy that's used in this game, how long would a full tank that size last?(aprox as I know size of room and plants make a difference)

hey i just came across the exact same thing. i was close to the end of my harvest. i chopped three and still had a sativa that had three weeks left. i run a dual lamp ballast 400w in a big closet. i also dont have a timer or hoses for my tank but listen. ive been letting it out pointing toward the plant and over a week or two the buds plumped up very nicley. it hadnt run out yet it was full i run it five times a twelve hour day for five to ten minutes plus fairly light when the fans are off my temp dont go over 85. like 4 liter per min. see i got lucky and mine has a regulator, still need solenoid snd flow meter timer etc. but yea it does work well for a small grow. i plan on still getting a whole different 20 lb tank setup for my flowering room and use this small one from its beer days go to my veg clone seedling areas. il get a pic up of the buds compared to the three other females i just harvested that had no co2 theyve been curing for two weeks. andvthe sativa thats still going seems to be absolutely loving the co2. peace from the east