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Co2 and Exhaust Fan

I recently built a Co2 generator and added it to my grow tent.

DIY - CO2 Generator

For the growers that are using Co2 do you see a significate lose of Co2 when running your fan? If I don't run the exhaust fan the humidity in my tent spikes to over 80% and the temperature was at 82 degrees when I checked my tent this afternoon. Once I turned on the exhaust fan the humidity dropped to 40% and the temp dropped to 75 degrees. I have also noticed that my plants do not seem to be drying out as quickly as before since I'm using a wet Co2 generator.
Should I run the exhaust fan when my humidity and temps rise or should I just run it 24/7 ?
Any comments would be appreciated.
 

Greg Mendel

Active Member
What's a "wet CO2 generator"? Yeast and sugar water in a bottle?

Even if you're a 20 lb bottle, unless you've to the valve cracked pretty wide, your exhaust fan is gonna suck all that lovely greenhouse gas right out.
 

HigherTheHigh

Well-Known Member
My understand with Co2 is if your running it you need to have your room sealed, if its not and you have an exhaust its a waste of time.

If your sat at 75f your in the perfect growing environment i would say, i stick at 25-27c for veg 23-25c.
 

Guy Cavallero

Well-Known Member
So co2 in a regular room is about 300ppm and you're generating 1500ppm in your tent?? Great little DIY job there.....!
 

Greg Mendel

Active Member
Wow, that's the biggest yeast rig I have ever seen. If you get tired of the mess and the smell and if want to keep dosing CO2, you can just buy a 20 lb tank and regulator at a welding supply house and add a needle valve from McMaster-Carr.
 
Wow, that's the biggest yeast rig I have ever seen. If you get tired of the mess and the smell and if want to keep dosing CO2, you can just buy a 20 lb tank and regulator at a welding supply house and add a needle valve from McMaster-Carr.
I figured this was the cheaper way to go. As far as the smell it's kind of a yeasty beer bread kind of a smell when I do happen to catch a whiff of it.
 

Greg Mendel

Active Member
I figured this was the cheaper way to go. As far as the smell it's kind of a yeasty beer bread kind of a smell when I do happen to catch a whiff of it.
The smell of a yeast CO2 rig always brings back happy memories of brewing beer and baking bread. If you do decide to upgrade to bottled CO2, this site tells you how to do it. (It's for a planted aquarium, but plants are plants, right?)
Setting Up a CO2-Injected Aquarium You can turn the CO2 on and off with a solenoid. Solenoid Valve Then all you can add a CO2 sensor to work that. Rocket science weed. ;)
 

MRXC

Well-Known Member
adding co2 is only sufficient if you pass the saturation point of the plants with light so having more than 1500w per square meter. And than you need to seal the room to keep it there. And keep it at 1500ppm to benefit the plants. Than you need to add a AC to keep temp down at 35c and you need a dehumidifier and humidifier to keep the RH in check. But still nice diy. Fun experiment. But everything that will be beter to this grow is cause of you and not the co2.
 

Greg Mendel

Active Member
adding co2 is only sufficient if you pass the saturation point of the plants with light so having more than 1500w per square meter. And than you need to seal the room to keep it there. And keep it at 1500ppm to benefit the plants. Than you need to add a AC to keep temp down at 35c and you need a dehumidifier and humidifier to keep the RH in check. But still nice diy. Fun experiment. But everything that will be beter to this grow is cause of you and not the co2.
I get what you're saying, but since CO2 is a plant's sole source of carbon and thus a critical nutrient, I would guess that increasing the CO2 around the plant even modestly could have significant effects even if all the other things you mention aren't present.

I don't have any experience with CO2 and cannabis (except with the gerbil a college friend kept in his grow room to increase the CO2 ;)), but I have had planted aquariums with CO2 supplementation for many years, and I can tell you that in those systems, bubbling in just a little extra CO2 can make an amazing difference.
 

TurboBucket

Well-Known Member
I get what you're saying, but since CO2 is a plant's sole source of carbon and thus a critical nutrient, I would guess that increasing the CO2 around the plant even modestly could have significant effects even if all the other things you mention aren't present.

I hear where your coming from. I don't think it's unreasonable to want to increase your co2 levels moderately. I've been wondering about this my self. I'm in a rural location, my grow is in the basement, away from living areas, my ambient co2 is most likely lower than someone in a city setting pulling air from inside a conditioned space with more people/sqft. Would I see a benefit by increasing my co2 levels even a little bit? Say I go from 250-300 to 500-600? No where near high enough to cause damage to plants, but should certainly increase assimilation. For the cost of a co2 bag or one of these yeast/sugar rigs what are you really out?
 
I finally received my aquarium heater from Amazon. Temps are holding at 78 degrees in my yeast bucket.

To MRXC:

I think the only thing dangerous about my Co2 rig is the consent craving for delicious homemade bread or maybe pretzels.
 

HigherTheHigh

Well-Known Member

Greg Mendel

Active Member
Would I see a benefit by increasing my co2 levels even a little bit? Say I go from 250-300 to 500-600?
That's not "a little bit," that's doubling it! I'll bet it could help, but the old standard advice applies of before you start hotrodding the system make sure all your basics are in place: great light, great soil, great nutes, great ventilation/circulation. Investing in and optimizing those first will probably give the biggest return on investment.
 

TurboBucket

Well-Known Member
That's not "a little bit," that's doubling it! I'll bet it could help, but the old standard advice applies of before you start hotrodding the system make sure all your basics are in place: great light, great soil, great nutes, great ventilation/circulation. Investing in and optimizing those first will probably give the biggest return on investment.
Haha
 
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