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Adding co2 at the rate air is exchanged

Cork144

Active member
Need some wisdom,


planning on exchanging the air in an area once every five to six minutes, with all lights on vented hoods,


running a co2 generator, say if it took five minutes to add 600 ppm co2 to the room, and the air is exchanged every 5-6 minutes, am I actually adding co2 or is it all being removed at the same rate


I dont mind having to constantly burn lpg if the PPM of the room is above 800 lets say even with the air exchange




someone tell me if im too high or not
 

AgentPothead

Just this guy, ya know?
I was under the impression adding co2 to a non sealed grow is a waste of time. Is the area you are exchanging air with sealed? If it's not you will just be sending your co2 right out your exhaust.
 

Cork144

Active member
in small setups I can imagine its a waste of time but in the middle of a large canopy I dont think ambient co2 levels are going to be as high as outdoor levels, therefor in my eyes any supplimentation is better than none, I'd rather spend 5-10 bucks a day in LPG if it will give me an extra lb or two
 

Cork144

Active member
But yes I understand your observation but my question is, is venting at the same rate it takes to add 600pm, going to get me above 800ppm, considering ambient levels are 350-400
 

AgentPothead

Just this guy, ya know?
No, you are venting it as it's being created. You would need to increase co2 generation or decrease your venting or setup a timer system where you are making co2 only when you aren't venting and make them staggered.
 

troutman

Seed Whore
I bet city air is richer than ambient 300 ppm.

More people farting = more carbon dioxide. :biggrin:

According to Wikipedia:

Carbon dioxide in Earth's atmosphere is a trace gas, currently (mid 2018) having a global
average concentration of 409 parts per million by volume or 622 parts per million by mass.
 

troutman

Seed Whore
Carbon dioxide levels are going up so I wouldn't worry about it.

With proper air exchange your plants will get all they want.

Save your $$$ for something else. :tiphat:
 

xADRIENx

New member
Need some wisdom,


planning on exchanging the air in an area once every five to six minutes, with all lights on vented hoods,


running a co2 generator, say if it took five minutes to add 600 ppm co2 to the room, and the air is exchanged every 5-6 minutes, am I actually adding co2 or is it all being removed at the same rate


I dont mind having to constantly burn lpg if the PPM of the room is above 800 lets say even with the air exchange




someone tell me if im too high or not

ive read the other responses and theres a point being made that your missing

for the plant to utilize the co2 it needs time to absorb it from the air

if you keep your ventilation on while the co2 is in there, then the plants arent gonna have enough time to absorb it from the air

to use co2 so that the plants can absorb it you need to turn your ventilation OFF for about an hour or so, keep your circulation fans ON

or think of it this way: if some one had to hold a glass of water so you could drink form it would it be better for them to throw the whole cup at you and hope you get some OR hold it to your lips and let you sip it?

*throwing it at you and hoping for the best = VENTILATION ON

*letting you sip so that you can get it all = VENTIALTION OFF with circulation fans blowing the co2 around the plants
 

Shmavis

Being-in-the-world
Need some wisdom,


planning on exchanging the air in an area once every five to six minutes, with all lights on vented hoods,


running a co2 generator, say if it took five minutes to add 600 ppm co2 to the room, and the air is exchanged every 5-6 minutes, am I actually adding co2 or is it all being removed at the same rate


I dont mind having to constantly burn lpg if the PPM of the room is above 800 lets say even with the air exchange




someone tell me if im too high or not

Grab yourself a CO2 meter first. If you’re willing to invest in supplementation, you’ll want one anyway, if not a multi-function controller with meter; if you do add CO2. You might find that ambient levels are higher than you suspect though, as others have said. I can tell you this: yes, you can maintain 800 PPM (and higher) with air exchange. Even with continuous air exchange instead of the timed exchange you propose. I have done so for many years. But my ambient levels are high to begin with.

There are missing points about your setup. First off, are you exhausting the grow area outside, or exhausting into the living area that you’re growing in? Are the lights exhausted to the outside, or a lung room? Is a lung room incorporated into the exchange in any way? Generator in the flower room or lung room? High CO2 levels will benefit best with higher temps and humidity. So watts may be relative to PPM levels. And factor the BTUs of the generator into your heat-load...

You said “add to”, referring to adding 600PPM, which implies you know your baseline... It pays to know your baseline. I would start there, with a meter, if you haven’t already.

Best of luck!

ive read the other responses and theres a point being made that your missing

for the plant to utilize the co2 it needs time to absorb it from the air

if you keep your ventilation on while the co2 is in there, then the plants arent gonna have enough time to absorb it from the air

to use co2 so that the plants can absorb it you need to turn your ventilation OFF for about an hour or so, keep your circulation fans ON

or think of it this way: if some one had to hold a glass of water so you could drink form it would it be better for them to throw the whole cup at you and hope you get some OR hold it to your lips and let you sip it?

*throwing it at you and hoping for the best = VENTILATION ON

*letting you sip so that you can get it all = VENTIALTION OFF with circulation fans blowing the co2 around the plants

Nice contributing first post. Welcome!

Good points. Levels can also be equalized with exchange so that saturation allows for constant sipping, as opposed to bursts of recharging - or having to chug or drown. :tiphat: Just another way to skin the cat.
 

Cork144

Active member
ive read the other responses and theres a point being made that your missing

for the plant to utilize the co2 it needs time to absorb it from the air

if you keep your ventilation on while the co2 is in there, then the plants arent gonna have enough time to absorb it from the air

to use co2 so that the plants can absorb it you need to turn your ventilation OFF for about an hour or so, keep your circulation fans ON

or think of it this way: if some one had to hold a glass of water so you could drink form it would it be better for them to throw the whole cup at you and hope you get some OR hold it to your lips and let you sip it?

*throwing it at you and hoping for the best = VENTILATION ON

*letting you sip so that you can get it all = VENTIALTION OFF with circulation fans blowing the co2 around the plants


if that was true then how are plants absorbing the ambient co2 in the air thats being pulled continually through grows, the air doesnt have to be stale for plants to capture co2.......can you only breathe if your stood still or there is no wind,,,,,,,,,,,,,,
 
Last edited:

Cork144

Active member
Grab yourself a CO2 meter first. If you’re willing to invest in supplementation, you’ll want one anyway, if not a multi-function controller with meter; if you do add CO2. You might find that ambient levels are higher than you suspect though, as others have said. I can tell you this: yes, you can maintain 800 PPM (and higher) with air exchange. Even with continuous air exchange instead of the timed exchange you propose. I have done so for many years. But my ambient levels are high to begin with.

There are missing points about your setup. First off, are you exhausting the grow area outside, or exhausting into the living area that you’re growing in? Are the lights exhausted to the outside, or a lung room? Is a lung room incorporated into the exchange in any way? Generator in the flower room or lung room? High CO2 levels will benefit best with higher temps and humidity. So watts may be relative to PPM levels. And factor the BTUs of the generator into your heat-load...

You said “add to”, referring to adding 600PPM, which implies you know your baseline... It pays to know your baseline. I would start there, with a meter, if you haven’t already.

Best of luck!


I plan on using a very large fan and filter in a very large area, set slow enough on the speed controller so that the rooms air would be 'completely' exchanged via volume every 5-6 minutes.


Do you think adding co2 in a seperate room where I pull my air inlet through could be a good way to boost the PPM of intake air


My friend is currently making me a room monitor with audino and a mhz16 sensor
 

Cork144

Active member
well while digging deeper, and realising if ventilating I'd probably need to double the LPG use, I'm thinking I need to burn about 600grams per hour, which is roughly 37CF/h co2 generation, meaning a 47kg bottle would last me 6.5 days during 12/12.


This is roughly 50quid to me a week.


11 weeks 12/12, 24 600w lights, 550quid in lpg for possibly double the ambient co2 levels......


anybody see why I think it could be a worth while investment now, even if it only gave me an extra 5percent yeild, over 24 lights that is atleast 10x what I spent into LPG.


no such thing as too costly,,,,,, just a matter of scale


I plan on using light movers, which to make maximum use of the areas which will be slightly more shaded as the light moves aways, time under the light, = having ample co2 for the photons to be captured and used during photosynthesis,
 

Shmavis

Being-in-the-world
...Do you think adding co2 in a seperate room where I pull my air inlet through could be a good way to boost the PPM of intake air

Sure. And pulling CO2 rich air sourced from another room will also reduce your heat-load.

If I now understand correctly, you want to continuously exhaust while supplementing CO2, (let’s leave aside the rate of exchange), is that right? Personally, instead of focusing on a timed air-exchange rate, I would shoot for slight negative pressure. If you mean to exhaust 24/7.

But if all you’re after is 800PPM, I say test first. Otherwise, xADRIENx’s point is valid. If you’re shutting down ventilation during supplementation - as is generally the consensus for non-sealed rooms - you are “charging” the room. Say up to 1500PPM, or higher, for timed bursts. That’s why many controllers automatically cut out exhaust function when supplementing CO2. But it's possible you're closer to that target (800) than you think. But then again, maybe not. Either way, it's in your benefit to know your baseline.

This is the ambient level in my room, with no plants or supplementation:
picture.php
 

Cork144

Active member
wont be shutting off the fan at all, just dimming it down to a much slower speed, where it would take 5-6 minutes to change the entire rooms volume of air, which I believe is already a fairly slow rate compared to what is normally required, is it not
 

Shmavis

Being-in-the-world
Exchange within 5-6 minutes is generally considered standard. Something else to consider is that if you opt to run the generator in the flower room itself, you’ll need to obtain negative pressure that isn’t creating a combustion issue for the generator. Make sure that when it fires its producing clean blue flame without yellowing or “pulling” toward the exhaust. I was surprised at how much negative pressure I could create without disturbing function of the generator.

There's some really informative threads here on lung rooms. They're worth a read. And air exchange at twice-per-minute is worth considering as well.
 

Cork144

Active member
Exchange within 5-6 minutes is generally considered standard. Something else to consider is that if you opt to run the generator in the flower room itself, you’ll need to obtain negative pressure that isn’t creating a combustion issue for the generator. Make sure that when it fires its producing clean blue flame without yellowing or “pulling” toward the exhaust. I was surprised at how much negative pressure I could create without disturbing function of the generator.

There's some really informative threads here on lung rooms. They're worth a read. And air exchange at twice-per-minute is worth considering as well.


mate thank you for actually advising me how it can be done instead of telling me it cant or that its a waste, legend
 

Iamnumber

Active member
in small setups I can imagine its a waste of time but in the middle of a large canopy I dont think ambient co2 levels are going to be as high as outdoor levels, therefor in my eyes any supplimentation is better than none, I'd rather spend 5-10 bucks a day in LPG if it will give me an extra lb or two


Aww.. Man..



You will be dumbing a ton of co2 to atmosphere to gain few/some bucks.. ?!? that is not a nice thing to do.


Please, I peg you.. go back to drawing board and reconsider what steps you would have to take to significantly lower your air exchange rate before adding a co2 to your setup.


You have not given a reason why you would have to exchange your air at such high rate so no pointers can be given.
 

Cork144

Active member
Aww.. Man..



You will be dumbing a ton of co2 to atmosphere to gain few/some bucks.. ?!? that is not a nice thing to do.


Please, I peg you.. go back to drawing board and reconsider what steps you would have to take to significantly lower your air exchange rate before adding a co2 to your setup.


You have not given a reason why you would have to exchange your air at such high rate so no pointers can be given.


I beg you to not believe the bollocks the system tells you about co2.... if they cared that much they would of tuned to hemp for paper years ago
 

AgentPothead

Just this guy, ya know?
You don't even have a meter to determine your current levels. Pumping more co2 that you are then going to exhaust is a waste. Go to your local hydro shop and ask them about supplementing co2 in a non sealed room. They will tell you it's a bad idea. And they literally want to sell you stuff.
 

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