DIY: Home Made CO2 Guide

do the release valve have to be level with the canopy or would it be better above the canopy thanks

Hey Ninja, do you think putting one of these bottles next to a tray of clones or barely rooted babies would help them out at all?

moodster said:

do the release valve have to be level with the canopy or would it be better above the canopy thanks

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Above will b fine, it will settle on the plants, so long as its not getting suckd straight out by the extraction fan.

hangshai said:

Hey Ninja, do you think putting one of these bottles next to a tray of clones or barely rooted babies would help them out at all?

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I cant imagine it wud help un-rooted clones, but if they have roots, then it should really help their photosynthesis.

IndieGrower said:

Not worth the effort.
C6H12O6 (glucose)

2 C2H5OH (ethyl alcohol) + 2 CO2
1cup sugar = 250grams/180grams(molar mass of glucose)=1.38mol glucose(sugar)

1.38mole x 44g(molar mass of carbon dioxide)= 60.72 grams carbon dioxide.

60.72g/1.98grams a liter=30.6liters carbon dioxide

so only about 30.5 liters would be produced over a week, and that is idealy so the actual gas is probably a lot less.

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Wrong.

1. Table sugar, which is being used here, is sucrose.
2. Sucrose is made up of both glucose and fructose units, both of which yeast can ferment.
3. You went from mentioning 2 moles of CO2 to using only 1 mole in your calculation. Using the correct number would double the amount of CO2 calculated.
4. You made no mention of the PPM increase.


Potentially useful constants/information :

- Bulk density of granulated sugar = 0.70 g/mL
- Molar mass of sucrose = 342.30 g/mol
- Molar mass of CO2 = 44.010 g/mol
- 1 mole of sucrose (C12H22O11) can be fermented to produce 4 moles of CO2
- 1 US cup = 236.588237 ml
- Molar volume of an ideal gas = 24.465 L/mol at 25 °C
- 10,000 PPM = 1 %
- PPM, when discussing gases, often times means PPM by volume. 1 PPM = 1 mL/m^3

So, ideally, one cup of sugar fermented by yeast could produce (I'm leaving out my calculations) = 1.94 moles of CO2 = 47.3 L of CO2

Suppose you have a closet grow with a volume of 2.24 cubic meters. To raise the PPM to 1500 you would need to add 1200 PPM to the atmosphere's 300 PPM.

An increase of 1200 PPM in this particular closet would require 2.69 Liters of CO2.

So I could theoretically meet these requirements 17.6 times with a perfectly fermented cup of sugar.

If you're curious how many times you can fill your grow room to 1500 PPM with 1 cup of ideally fermented sugar, divide 39.42 by your room's volume in cubic meters.

Short story long, this isn't a bad method for adding CO2 to your grow room, but it should probably be scaled up. My calculations also do not take into account if your room is leaking, or how much CO2 your plants consume.

I'm definitely up for trying this method- although I would scale it up if I did.

ChemisTree said:

Wrong.

1. Table sugar, which is being used here, is sucrose.
2. Sucrose is made up of both glucose and fructose units, both of which yeast can ferment.
3. You went from mentioning 2 moles of CO2 to using only 1 mole in your calculation. Using the correct number would double the amount of CO2 calculated.
4. You made no mention of the PPM increase.


Potentially useful constants/information :

- Bulk density of granulated sugar = 0.70 g/mL
- Molar mass of sucrose = 342.30 g/mol
- Molar mass of CO2 = 44.010 g/mol
- 1 mole of sucrose (C12H22O11) can be fermented to produce 4 moles of CO2
- 1 US cup = 236.588237 ml
- Molar volume of an ideal gas = 24.465 L/mol at 25 °C
- 10,000 PPM = 1 %
- PPM, when discussing gases, often times means PPM by volume. 1 PPM = 1 mL/m^3

So, ideally, one cup of sugar fermented by yeast could produce (I'm leaving out my calculations) = 1.94 moles of CO2 = 47.3 L of CO2

Suppose you have a closet grow with a volume of 2.24 cubic meters. To raise the PPM to 1500 you would need to add 1200 PPM to the atmosphere's 300 PPM.

An increase of 1200 PPM in this particular closet would require 2.69 Liters of CO2.

So I could theoretically meet these requirements 17.6 times with a perfectly fermented cup of sugar.

If you're curious how many times you can fill your grow room to 1500 PPM with 1 cup of ideally fermented sugar, divide 39.42 by your room's volume in cubic meters.

Short story long, this isn't a bad method for adding CO2 to your grow room, but it should probably be scaled up. My calculations also do not take into account if your room is leaking, or how much CO2 your plants consume.

I'm definitely up for trying this method- although I would scale it up if I did.

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Thanks for the input. It's good 2c some ppl who think out of the box. Scaling up would b recommended for a grow room. The 2L bottle is meant mainly for a closet or small tent.
Thanks again +Rep.

XxNinjaxX said:

Thanks for the input. It's good 2c some ppl who think out of the box. Scaling up would b recommended for a grow room. The 2L bottle is meant mainly for a closet or small tent.
Thanks again +Rep.

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No problem, I hope to get a CO2 meter and see what kind of increase I can get in a closed system closet grow.

It's a great idea in my opinion- you can pick up the ingredients at your local supermarket and increase the rate of your grow. We'll see how it goes.

just put one of these together and looks as though air is going into the 2L bottle, the bubble within the air lock should be bubbling the other way. Why would this be happening?

how do you think this would work with say: a 5gal bucket w/ 3 bubbler heads, mix of 5 cup sugar 5 tblspn yeast 2 gals water. maybe it'd be more like the 1500ppm like haveing 5 small ones. maybeeven last 3-4 weeks?

growGuRoo said:

just put one of these together and looks as though air is going into the 2L bottle, the bubble within the air lock should be bubbling the other way. Why would this be happening?

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just got to sort itself out leave it under ur lights should start going forward if not its not air tight

mrduke said:

how do you think this would work with say: a 5gal bucket w/ 3 bubbler heads, mix of 5 cup sugar 5 tblspn yeast 2 gals water. maybe it'd be more like the 1500ppm like haveing 5 small ones. maybeeven last 3-4 weeks?

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::: bump

does the amount of water in the bubbler effect its CO2 output rate? do the chambers need refilling due to evaporation/bubbling much?

Well after doing harvests back to back utilizing this technique and not using it, I have come to the conclusion that this is a waste of time and sugar. Maybe in a totally air tight environment, this might have noticeable affects, but if you have an airtight grow op, chances are everything is running very close to optimal and you can afford a CO2 generator and avoid dealing with this crap.

It's a good idea, but filling multiple bottles with sugar water is a hassle, and generally not worth the cost of sugar and yeast in my opinion. I always keep yeast and sugar around for cooking. A jar of yeast will last me a year of pizza/bagle/rolls/buns/ dough, but only last about a month of filling these "CO2 generators." Seriously, if you're too broke to afford an actual generator, it's not worth adding CO2 to your operation. I suggest you work on perfecting other areas. A good exhaust system with proper fresh intakes will supply way more CO2 than these 2L bottles...

Now with that being said, I do continue to ferment my homebrew beer in my grow room. I usually have 5-10 gallons fermenting at any given time. Truthfully, I haven't noticed much of an increase in plant production (and if I can't notice much with 10 gallons fermenting, I doubt you can with your 2L bottles)... but if I'm going to be brewing beer might as well do it back in the grow room where the temps are stable and any increase of CO2 will be beneficial.

cool tip i will try it some time

repvip said:

Hmm.. I better restate this--I do not recommend it, but it would work in a pinch. There. For more information on burning fuels for CO2 enrinchment,
http://www.hortnet.co.nz/publications/science/n/neder/co2_nr5.htm#top
go there. There may be other gasses emitted that are not so great. However, candles seem safe enough for humans, but I digress.

Not sure if it's been answered or not, but yes you can supply too much CO2. There is a chart somewhere, but it looks the same as every other macronutrient uptake versus plant growth chart out there--meaning growth exponentially increases with increased macronutrient, at first, then levels off, then becomes toxic and decreases. I cannot find the chart, but plant growth is 100% at ~350ppm, and increases sharply, but quickly not as rapid to ~130% at 1100ppm. It goes up slightly more, maybe ~140% up to 1500ppm, but at 2000ppm plant growth starts dropping again, as toxic levels can happen. Yes, with humans too.

I've actually used this fermentation method before I had tanks, and I'm curious if it really works.. I'm gonna do an experiment today and post some pics laters using my ppm meter.

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I went through the link you gave, very good read. this morning i fired up a 1# propane bottle with my adjustable torch tip for 45 minutes and i think i see a noticable growth in just 12 hours and they are really dark green today. I'm gunna try this for a week , but in the mean time i want to make the airlock thing out of some airline. I will just try and mimick the one pictured and use a bread tie or something and stick it in a bottle cap. I put the torch behind my fan that blows all over my plants and my temps go from 76 f without it, to 81 f with the torch on its lowest setting. what do ya think.

sixstring2112 said:

I put the torch behind my fan that blows all over my plants and my temps go from 76 f without it, to 81 f with the torch on its lowest setting. what do ya think.

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Sounds like a good way to spread it around the room. Also, raising ur temps that little bit is encouraged as plants can use more CO2 @ hotter temps.

I thought i read that temps around 80 were better for co2, thanks. what about my plan to make the airlock out of regular tubing, has anyone tried this or is it a waste of time. I don't have a wine shop around me.

I've got 3 ladies in a 2x4x5 ft tent...I run a weak (80cfm) exhaust fan connected to my cool tube and the temps are usually @ 82-84 with a couple of circulating fans...I plan to leave the little exhaust fan on and maybe put 2 of these co2 thingys since the fan will be on during the light period???? I'm hoping that having 2 will offset the exhaust fan and get the ppm higher than 1 DIY co2 thing...thanks for the help...great thread! Shoot any suggestions if you've got 'em.

sixstring2112 said:

I thought i read that temps around 80 were better for co2, thanks. what about my plan to make the airlock out of regular tubing, has anyone tried this or is it a waste of time. I don't have a wine shop around me.

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It seems like a sound theory..

The All Day Toker said:

I've got 3 ladies in a 2x4x5 ft tent...I run a weak (80cfm) exhaust fan connected to my cool tube and the temps are usually @ 82-84 with a couple of circulating fans...I plan to leave the little exhaust fan on and maybe put 2 of these co2 thingys since the fan will be on during the light period???? I'm hoping that having 2 will offset the exhaust fan and get the ppm higher than 1 DIY co2 thing...thanks for the help...great thread! Shoot any suggestions if you've got 'em.

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My 1st suggestion to you would be to lower your lights.. With Temps that low and through a cool tube you should b cutting that distance in half.
Also maybe have ur outake fan come on @ 4 hr intervals in ur dark period to get some fresh air into the room.

Thanks, I had just tied down 1 of my girls that took off and was level with the tube 4 a day...it's a 400w hps and the bubbleberry on the right is @ right about perfect height (temp wise...the pic angle doesn't show how close it is)...and the purple passion in the middle has had root rot and is kind of a runt, it's gotten about as tall as the other plants since the pic but not a ton of new growth...I was debating on transferring from DWC to soil to kill the root B.S....but I think I'd shock her so I'm going to wait I think...any thoughts?

This is great im gonna try it.