CO2 Canister Generator for 4x8 Tent Using Bicarb Soda + Citric Acid

Hey all,

I started doing some research late last night with regards to CO2 generators, and found many different threads with plenty of opinions, and only a couple regarding these metal CO2 canisters which you simply mix Citric Acid, Baking Soda and water to complete the reaction. Quickly sealing the canister will allow the build-up of CO2 over the course of a few minutes to a few hours.



I guess my question is - Has anyone used these, and can you vouch for them over alternative methods? There are plenty of other ways to generate and produce CO2, however, most are either expensive in the long run (Such as Exhale bags), or potentially dangerous for an indoor grow (Butane/LPG burners).

I am yet to do my own due diligence and research further into this topic, though I wanted to hear some fresh thoughts on these canisters - I was thinking of purchasing two 2L canisters, placing one in each half of the 4x8 tent. I believe these can produce up to 70-100 Grams of CO2, though I'm not sure if that's much at all? I also came across a useful YouTube video that might be beneficial - in said video is a response from a Reddit user who broke down the methodology to the madness, and provided accurate mixtures to get the optimal reaction from the CO2 bottles.

Part 1 - (Skip to 0:44 - How Much Co2 Is Produced? )
Part 2 -
With that being said, it was recommended for a 1:312 ratio (bicarb:citric), or 100g bicarb and 131.2g of citric acid. Though not sure on the amount of water - I presume approximately 150-200g of water for the mentioned mixture.

This definitely has my keen eye and I would love to hear your thoughts on this. Let's discuss!

RockStonedJesus said:

Hey all,

I started doing some research late last night with regards to CO2 generators, and found many different threads with plenty of opinions, and only a couple regarding these metal CO2 canisters which you simply mix Citric Acid, Baking Soda and water to complete the reaction. Quickly sealing the canister will allow the build-up of CO2 over the course of a few minutes to a few hours.

View attachment 4928275

I guess my question is - Has anyone used these, and can you vouch for them over alternative methods? There are plenty of other ways to generate and produce CO2, however, most are either expensive in the long run (Such as Exhale bags), or potentially dangerous for an indoor grow (Butane/LPG burners).

I am yet to do my own due diligence and research further into this topic, though I wanted to hear some fresh thoughts on these canisters - I was thinking of purchasing two 2L canisters, placing one in each half of the 4x8 tent. I believe these can produce up to 70-100 Grams of CO2, though I'm not sure if that's much at all? I also came across a useful YouTube video that might be beneficial - in said video is a response from a Reddit user who broke down the methodology to the madness, and provided accurate mixtures to get the optimal reaction from the CO2 bottles.

Part 1 -

(Skip to 0:44 - How Much Co2 Is Produced? )
Part 2 -

With that being said, it was recommended for a 1:312 ratio (bicarb:citric), or 100g bicarb and 131.2g of citric acid. Though not sure on the amount of water - I presume approximately 150-200g of water for the mentioned mixture.

This definitely has my keen eye and I would love to hear your thoughts on this. Let's discuss!

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Placebo. It generates so little carbon dioxide that there will be no effect on the grow. You will do better with a high rate of air exchange. Spend your money elsewhere.

How are you proposing to detect and record actual CO2 levels in the grow space?

cannabineer said:

Placebo. It generates so little carbon dioxide that there will be no effect on the grow. You will do better with a high rate of air exchange. Spend your money elsewhere.

How are you proposing to detect and record actual CO2 levels in the grow space?

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Interesting. Do you have first-hand experience or have reputable sources to back that claim of being a placebo up? Interested to hear more, in-depth about these generators and why it is a placebo?

I have not gone that far with regards to detect and record CO2 levels - do you have any recommendations?

RockStonedJesus said:

Interesting. Do you have first-hand experience or have reputable sources to back that claim of being a placebo up? Interested to hear more, in-depth about these generators and why it is a placebo?

I have not gone that far with regards to detect and record CO2 levels - do you have any recommendations?

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No; I’m going on first principles. I taught chemistry.

The only way to know is to have real-time gas level sensing. I looked into that maybe 2 years ago and could not afford the $1k equipment.

I am calling placebo because that can be effectively sold. I don’t resent folks marketing a feelgood solution, but I don’t give them money.

cannabineer said:

No; I’m going on first principles. I taught chemistry.

The only way to know is to have real-time gas level sensing. I looked into that maybe 2 years ago and could not afford the $1k equipment.

I am calling placebo because that can be effectively sold. I don’t resent folks marketing a feelgood solution, but I don’t give them money.

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I see, thanks for clarifying things up.
With that being said, how would such a CO2 canister compare to the likes of an Exhale bag, as example? I am trying to gauge whether these CO2 canisters are truly snake oil, or if there is some sort of science behind them? I note you mentioned that it generates so little CO2, however, define "So little"? Because when it comes to comparing a CO2 canister/generator to an Exhale bag or similar, I am trying to ascertain which works out to be cheaper. Keen to understand more about these available options.

RockStonedJesus said:

I see, thanks for clarifying things up.
With that being said, how would such a CO2 canister compare to the likes of an Exhale bag, as example? I am trying to gauge whether these CO2 canisters are truly snake oil, or if there is some sort of science behind them? I note you mentioned that it generates so little CO2, however, define "So little"? Because when it comes to comparing a CO2 canister/generator to an Exhale bag or similar, I am trying to ascertain which works out to be cheaper. Keen to understand more about these available options.

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I believe bags and canisters etc. simply do not provide a significant benefit. They don’t make enough compound. The big guys use cylinders containing hundreds of pounds of carbon dioxide, or propane burners with comparable output. And they control the emitter or burner by monitoring gas levels in a sealed space.

That said, I’ve never seen it done. So take my maunderings with a grain of salt.

cannabineer said:

No; I’m going on first principles. I taught chemistry.

The only way to know is to have real-time gas level sensing. I looked into that maybe 2 years ago and could not afford the $1k equipment.

I am calling placebo because that can be effectively sold. I don’t resent folks marketing a feelgood solution, but I don’t give them money.

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Lol when you said from first principals I thought you meant you calculated how many mol of CO2 that reaction produces and deduced per the quantity of reactants and the volume of the grow space no appreciable amount of CO2 would be developed.

MidnightSun72 said:

Lol when you said from first principals I thought you meant you calculated how many mol of CO2 that reaction produces and deduced per the quantity of reactants and the volume of the grow space no appreciable amount of CO2 would be developed.

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I didn’t go that far. Since the quantity from a bag or canister is a few mol at most, and air exchange in a healthy grow space is several cubic meters an hour, I am wagering that the increment is a percent or two over ambient. I’m good with being proven wrong.

cannabineer said:

I believe bags and canisters etc. simply do not provide a significant benefit. They don’t make enough compound. The big guys use cylinders containing hundreds of pounds of carbon dioxide, or propane burners with comparable output. And they control the emitter or burner by monitoring gas levels in a sealed space.

That said, I’ve never seen it done. So take my maunderings with a grain of salt.

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Thanks for your word of advice, and look, you are definitely right - big operations indeed use cylinders/propane burners with fancy equiptment, and that's definitely in a whole other ball park, especially comparing them to bags/generators.

I would be keen to hear from someone who has actually tinkered around with these generators and their thoughts, too, as it's always good to get a few different opinions. If Exhale bags and generator canisters do not offer any benifit, then we can consider it snake oil? Or is there more to it than that?

RockStonedJesus said:

Thanks for your word of advice, and look, you are definitely right - big operations indeed use cylinders/propane burners with fancy equiptment, and that's definitely in a whole other ball park, especially comparing them to bags/generators.

I would be keen to hear from someone who has actually tinkered around with these generators and their thoughts, too, as it's always good to get a few different opinions. If Exhale bags and generator canisters do not offer any benifit, then we can consider it snake oil? Or is there more to it than that?

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It is my belief that it is cynical marketing. Since I have no direct or spoken experience, what I have said here is naked opinion.

cannabineer said:

I didn’t go that far. Since the quantity from a bag or canister is a few mol at most, and air exchange in a healthy grow space is several cubic meters an hour, I am wagering that the increment is a percent or two over ambient. I’m good with being proven wrong.

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You missed the real CO2 thread, do a search on CO2 and member weedvin. You'll love it

If you look around for a used 25# tank, buy a co2 regulator ($40 bucks on amazon), and a timer its not that expensive to set up. Google "co2 calculator grow room" to calculate how much you need to disperse to fill your area and viola an inexpensive way to add co2. I know you were asking about that particular system but personally I wouldn't waste my time or money on it.

jcdws602 said:

If you look around for a used 25# tank, buy a co2 regulator ($40 bucks on amazon), and a timer its not that expensive to set up. Google "co2 calculator grow room" to calculate how much you need to disperse to fill your area and viola an inexpensive way to add co2. I know you were asking about that particular product but personally I wouldn't waste my time or money on it.

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I'm curious about when you think it's good to add CO2 to a grow?

curious2garden said:

I'm curious about when you think it's good to add CO2 to a grow?

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When you have a sealed room and high PPFD environment.

curious2garden said:

I'm curious about when you think it's good to add CO2 to a grow?

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Im not sure if you're asking about when as in a plant's life cycle or as in when a person as a grower but either way supplemental co2 is beneficial through the entire plants life cycle. Less in late flower amd more in the first weeks of flower production. As a grower I would only recommend adding co2 for an experienced grower using a sealed and dialed in environment. Of course to benefit from the elevated co2 light, temperature, and nutrients will have to accommodate the increase.

MidnightSun72 said:

When you have a sealed room and high PPFD environment.

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I completely agree about a sealed room. It's the high PPFD I'm not so sure about. It's the RuBisCo enzyme that starts the enzymatic carbon fixation reaction and that is a function of heat, specifically leaf temperature not necessarily ambient room temperature. I always thought of it as a grow enhancer and not something a beginner really needs because until you really get your grow entirely dialed in it's not going to really help you all that much.

Thank you for your answer! I appreciate it.

jcdws602 said:

Im not sure if you're asking about when as in a plant's life cycle or as in when a person as a grower but either way supplemental co2 is beneficial through the entire plants life cycle. Less in late flower amd more in the first weeks of flower production. As a grower I would only recommend adding co2 for an experienced grower using a sealed and dialed in environment. Of course to benefit from the elevated co2 light, temperature, and nutrients will have to accommodate the increase.

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How long have you been growing?

curious2garden said:

I completely agree about a sealed room. It's the high PPFD I'm not so sure about. It's the RuBisCo enzyme that starts the enzymatic carbon fixation reaction and that is a function of heat, specifically leaf temperature not necessarily ambient room temperature. I always thought of it as a grow enhancer and not something a beginner really needs because until you really get your grow entirely dialed in it's not going to really help you all that much.

Thank you for your answer! I appreciate it.


How long have you been growing?

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Just google increase co2 and ppfd and you will find peer reviewed studies that explain the benefits of increasing ppfd in environments with elevated co2 levels. Some pretty interesting reads for sure. And to answer your question almost 2 decades off and on and still learning.

jcdws602 said:

Just google increase co2 and ppfd and you will find peer reviewed studies that explain the benefits of increasing ppfd in environments with elevated co2 levels. Some pretty interesting reads for sure. And to answer your question almost 2 decades off and on and still learning.

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Interesting, I keep toying with the idea of sealing off my room and using CO2. I grow in a high heat environment. But I don't need more pot since I don't sell. So it seems less important to me. Also my grow is never completely dialed in since I'm always running different genetics.

We get a lot of new growers who immediately look at doing the complex and unnecessary and since you're new here I thought I'd ask. Anyway listen to cannabineer about what he told you about equipment. He's a PhD Organic Chemist and he knows his stuff. I'd listen to @jcdws602 and just get a tank regulator and controller when you get ready to seal.

Best of luck on your grow.

curious2garden said:

Interesting, I keep toying with the idea of sealing off my room and using CO2. I grow in a high heat environment. But I don't need more pot since I don't sell. So it seems less important to me. Also my grow is never completely dialed in since I'm always running different genetics.

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I was referring more so to the environment opposed the to the cultivars but its definitely not necessary. I live in very hot region so venting in 115 degree f. air in summer is not ideal. Also being able to run higher temperatures lowers cooling cost for me. To be honest the main reason is that I like to have complete control of all the variables of my grows. Its the reason I prefer growing indoors. Also I thought you directed the question "how long have you been growing" at me.

jcdws602 said:

I was referring more so to the environment opposed the to the cultivars but its definitely not necessary. I live in very hot region so venting in 115 degree f. air in summer is not ideal. Also being able to run higher temperatures lowers cooling cost for me. To be honest the main reason is that I like to have complete control of all the variables of my grows. Its the reason I prefer growing indoors. Also I thought you directed the question "how long have you been growing" at me.

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No, no that was to the new member and absolutely no insult intended to either of you. I'm in the Mojave Desert so I'm dealing with a 100 degree canopy indoors. So I've pondered about CO2 in my head a lot. Usually from June to October.

I mixed your screen names around For growing way outside the VPD parameters I grow some great pot. This particular screw up was brought to you by Wedding Cake.