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CO2 meter

J

John LOQUE

Member
High !
I have got a CO2 meter for several years, but the minimum value it shows is 350 ppm. So i don't know how much under 350 ppm it is really.

So my outside air is 350 ppm or under, that's all i know...

But i thought we were far above 400 ppm for a while now because of the pollution...

I don't think my plants are lacking of CO2 because they grow well, maybe the meter is wrong...

Have you seen grow rooms at 200 ppm because plants have consumed all the CO2?

Bye
 
Koondense

Koondense

Well-known member
Veteran
Easy way to test it is to put it in a small room with someone inside, close all access and see how the co2 value changes(or just exhale in a bag with the meter inside) . Maybe it doesnt work properly at all. I would test this before any other further testing.



Cheers
 
unnamedmike

unnamedmike

Well-known member
Hi there.
what the co2 minimum level there? I live in a low polluted area, surrounded by jungle, near the sea, and my outdoor co2 minimum is never below 340ppm. My co2 meter is able to meter from 1ppm to 2000/5000ppm. When the co2 go below 600 ppm i can see that something is going wrong.

If i can ask ... why are you running this low co2 level ?
 
J

John LOQUE

Member
You did not anderstand me, sure because i don't speak correctly.
The CO2 meter works, when i work in the room, the level raises, as if i burn gaz, for instance. No problem for that. But it's low limit seems to be 350 because i have never seen it under 350. If i don't go to the room during 6 hours for instance, the level goes down to 350 ppm. Or the plants have eaten all the CO2, or the exhaust fan to outside has changed the air.
If i put this meter outside, where i live, it says 350.
Generally when i see it at 350, i stay breathing in the room. As i have often something to do inside the room, they have enough CO2.

I've read that plants absorb CO2 untill 200 ppm, after they merely stop photosynthesis. But i could never verify...in my grow room.
 
unnamedmike

unnamedmike

Well-known member
John LOQUE said:
You did not anderstand me, sure because i don't speak correctly.
The CO2 meter works, when i work in the room, the level raises, as if i burn gaz, for instance. No problem for that. But it's low limit seems to be 350 because i have never seen it under 350. If i don't go to the room during 6 hours for instance, the level goes down to 350 ppm. Or the plants have eaten all the CO2, or the exhaust fan to outside has changed the air.
If i put this meter outside, where i live, it says 350.
Generally when i see it at 350, i stay breathing in the room. As i have often something to do inside the room, they have enough CO2.

I've read that plants absorb CO2 untill 200 ppm, after they merely stop photosynthesis. But i could never verify...in my grow room.
Click to expand...

Sorry, my fault, my poor explaining :shucks:
 
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H

Horselover Fat

Member
Veteran
John LOQUE said:
I've read that plants absorb CO2 untill 200 ppm, after they merely stop photosynthesis. But i could never verify...in my grow room.
Click to expand...

I think it would just slow growth and if there was very little co2 the plant would eventually run out of energy. The part of photosynthesis where co2 is used can also run on oxygen, but that merely reproduces the energy put in.
 
TahoeTops

TahoeTops

Active member
John LOQUE said:
You did not anderstand me, sure because i don't speak correctly.
The CO2 meter works, when i work in the room, the level raises, as if i burn gaz, for instance. No problem for that. But it's low limit seems to be 350 because i have never seen it under 350. If i don't go to the room during 6 hours for instance, the level goes down to 350 ppm. Or the plants have eaten all the CO2, or the exhaust fan to outside has changed the air.
If i put this meter outside, where i live, it says 350.
Generally when i see it at 350, i stay breathing in the room. As i have often something to do inside the room, they have enough CO2.
Click to expand...


I imagine your ambient air is 350. So it will not go below that.





I've read that plants absorb CO2 untill 200 ppm, after they merely stop photosynthesis. But i could never verify...in my grow room.
Click to expand...


But I am confused when you say they absorb until 200 ppm. Do you mean that when the CO2 levels drop below 200 ppm, growth stops?


Is your room completely sealed? Do you think your room is below 350 ppm? If so, why?
 
TahoeTops

TahoeTops

Active member
What kind of meter is it? Can you post a pic of it?



What happens to the reading when you blow a lungfull of air at it? Does it spike up then fall back down to 350 gradually?
 
J

John LOQUE

Member
When i breathe on it, i've have to wait a little bit before it climbs slowly, and after i guess it falls back more slowly, i say i guess because if i stay there it won't fall down. The thermometer has 2 degrees more than normal, and for RH, i don't know, because i have 3 hygrometer and 3 different readings... :D
 

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TahoeTops

TahoeTops

Active member
If you breathe on the sensor, it should immediately spike up and then fade back down. I looked up you meter and it does say it can read from 0-9999ppm.


It's possible you have a bad sensor. When was the last time you calibrated it?


If it is always reading around 350, then I have to assume you are not adding co2 to your room. If so, why not?


350 is within the 300-500ppm normal range of ambient air.
 
J

John LOQUE

Member
I did not know i had to calibrate it. Never did so...
Yes they say from 0 to 9999 ppm, but why never under 350 sharp? I don't believe it's really 350... Not a big deal anyway...
 
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