CO2 bottle size

Anyone regret buying a 50lb bottle? Love the idea of not having to change out all the time, but dread the thought of hauling it to get refilled. Thinking of a few 20lbers

CO2 is not worth it for the average grower.

For CO2 to be effective you will need adequate light (over 1,200 PPFD) and a sealed room to push the partial pressures up. Generally the biggest benefit is during veg. To accomplish this you will have to up your game on environmental control: run an AC split and a dehumidifier to manage high temps and RH. If running a closed system for any length of time you will need to pump O to the roots to avoid suffocating the plant (roots need O). Usually growers with CO2 run hydro to push both air to the roots and insane salt levels (2,000 ppm plus).

Welcome to the forum.


I’d regret buying any CO2 probably. I’m happy just standing in the room and breathing on my plants, and they seem happier too. Put a CO2 meter in your grow space and decide if it’s low enough that it needs supplementation, considering exhaust and all the other factors Midwest mentioned.

I will come hang out with my plants for about 30 minutes in the morning with lights on and watch my room (13x9) go from ~450ppms of CO2 to around 650 just by existing. It can climb up to 700+ if my dogs come chill with me, too.

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I tried CO2 when I started growing inside. I had CO2 PPM levels at 450 - 500 normally. Supplementing CO2 made no difference.


Yeah, I don’t think it would stay in my environment long enough for my ladies to care.

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:point_up_2: Ditto :love_you_gesture:

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Once we pass into November the grow tent “conditions” will be perfect to turn the gas on until March. A 20lb bottle is 40$, and I can do 2 grows per fill.
Let me preface by saying I’m in no way arguing an angle on its usage…but I’ve found a few peculiar things to happen when it’s on.
(I turn on 2 weeks before flower, and run till 5/6ish weeks into flower) . The stretch across canopy was accentuated… the flip to 12 showed nearly overnight… Like hairs in a day… The extreme temperature mistakes (101°f)made never stunted them… the density of bud was noticable.
Add: they were thirsty every day, and I ran the DLI at 65.

I had the autopilot monitor clocking 900 at start, and 1200 by wk4.
My scenario as a winter use will not recuperate cost for a long while, but I look at it like a nutrient cost (that makes me feel better.
Lol) Yes, the 400ppms from the atmosphere easily produce Lbs. Per plant, so what’s the point…

In retrospect…Shoulda put the funds towards a mini split


I use 50 lb bottle co2 not sure if thats helps but these pictures are 24hrs apart if that

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I have a single 20# bottle, and a 5#. I run CO2 at 1000 PPM and I’m sure it makes a significant difference. 100% hydro.

I’d hate to have to lug a 50# bottle around. I drain the 20#, put the 5# on, exchange the 20# and swap it back in (the 5# bottle is both a backup for the tent and for the kegerator).

Definitely takes some twiddling to get temp & humidity & CO2 & lights all hitting on all cylinders. My only cooling is pumping in air from outside, so that costs me CO2 and doesn’t cool as well as AC would.

interesting theme. thanks - what strain are those in purple?