I read that I could make CO2 with a cup of suger, a TBSP of dry yeast and a gallon of water in a jug.
But I don't think that will be enough for my grow room that is 800 cu ft.
I was thinking of maybe useing 5 lbs of sugar and a cup of dry yeast and mixing 15 ga of water in a 20ga fish tank, Do you think that that would produce enough CO2

post the link where you read this

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be wise legalize

its actually in the grow FAQ

here is the link

http://www.rollitup.org/view.php?pg=...article&id=286

idk after reading it i saw it only done with a little bottle mixing that much baking soda and yeast might be dangerious but gl either way i would suggest just haveing little bottle everywhere its a pain but worth it in the end Home Made Co2 Tutorial

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be wise legalize

you need to shake it up can u shake 15 gallons of water weight 8.35 lbs so 125.25lbs haha

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be wise legalize

if u want get some empty 2L milk cartons and fill wit warm water and mix in 2 tbls sp of sugar and a pack of bread yeast and shake, as u sayed, i done this aswell as i wanted they to grow as well as possible, but i f u have a ventilation system then the co2 will fly right out the vent, i think u dont really need extra co2, good soil and lights and proper watering and nutes and that all they need.... GL

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When fascism comes to America, it will be wrapped in the flag and carrying the cross. -Sinclair Lewis

I can stir it or put an air stone in it

if you use too much yeast it may expand and come up out of your container. this happened to me with a 1 gal container and i had yeast everywhere. once it dries its a pain to clean. and also it stinks terribly so if using a 15 gal container the stench may be so rancid you wont want to even go near it. when disposing of it (i had mine in a hbunch of smaller bottles) I went to pour it out and almost puked. also if using an air stone you might want to have it on a timer. this method is best used when the lights 1st come on when the room is at its coolest. too much co2 can be dangerous and i dont know why but i read somewhere that its more dangerous in hotter temps.

You are pretty correct.. It adds CO2, but in 800cuft a weak gallon won't do much at all.. I've been meaning to start a CO2 thread to explain what I know regarding fermenting, and Calculations.. I think I'll actually get started on that.. Keep an eye on the DIY subforum in General Growing..