High Tide Aquatics

CO2 meter accuracy

R

richiev

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Does anyone have experience with CO2 meters and any cross-references to their accuracy? I'm speaking in regards to the club one and also others.

I'm asking because I was ordering some TDS sensors off aliexpress, and it just so happened the place I ordered from also had CO2 sensor kits. It was $20, so I bought one, with the expectation I can pretty trivially plug it into an ESP32/Arduino and have my own CO2 sensor. I have no idea though if it'll be accurate/precise, but for $20 it seemed like another fun little project. I'll eventually borrow the club one and do a comparison.

Anyone have experience with various meters and know if there's meaningful accuracy differences between them?
 
Would obviously depend on the sensor you use. I use a Telaire T8100-D that is connected to Apex via a 0-5V input an on ASM module.

Here are the stats (left column) on it:

B230E991-7891-44AB-B6E0-25D1FBDAA705.png


From: https://www.amphenol-sensors.com/en/telaire/co2/526-co2-transmitters/3307-t8100
 
Not officially calibrated to a reference standard as far as I know, but I think the CO2 meter the club lends out is pretty accurate. It reads out about 420 ppm outside, which is what it should be, and goes up and down as expected.
 
RandyC said:
Would obviously depend on the sensor you use. I use a Telaire T8100-D that is connected to Apex via a 0-5V input an on ASM module.

Here are the stats (left column) on it:

View attachment 46770

From: https://www.amphenol-sensors.com/en/telaire/co2/526-co2-transmitters/3307-t8100
Click to expand...
That's the most obvious answer, "read the F'ing manual"! I should have started there. Seems the $20 sensor has comparable values, but TBD if they actually perform that.

If anyone would like a ~$30-$40 WiFi enabled CO2 sensor LMK. I can buy some more once I prove this out and it should be pretty easy to set it up. However that's going to be a bit, because the first sensors aren't even arriving until May or June!

JVU said:
Not officially calibrated to a reference standard as far as I know, but I think the CO2 meter the club lends out is pretty accurate. It reads out about 420 ppm outside, which is what it should be, and goes up and down as expected.
Click to expand...
Ah, that's also an obvious answer. Use the normal world as a reference. I wonder if they cheat though. Kind of how cheap bathroom scales magically have perfect precision, if you step off and back on you get the exact same reading, when in reality it's faking it and showing you t previous result. Or how cheap kitchen scales fake accuracy by doing the same thing, but also automatically converting things like 9.9g to 10g so it looks like it's perfectly measuring. That last ones been screwing me as I try and calibrate things based on water weight.

Regardless, measuring outside is a great idea and I can eventually grab the club meter!
 
I believe the industrial ones like randy mentioned "self calibrate" by taking the lowest reading over a period of time and assuming that is ~400. I'll have to look back, when I set mine up I remember reading about that. They assume it's in an office building what is mostly vacant over a weekend, and therefore has time to equilibrate with outside air.
 
Meshmez said:
I believe the industrial ones like randy mentioned "self calibrate" by taking the lowest reading over a period of time and assuming that is ~400. I'll have to look back, when I set mine up I remember reading about that. They assume it's in an office building what is mostly vacant over a weekend, and therefore has time to equilibrate with outside air.
Click to expand...
Here it is from the telaire manual:
Screenshot_20230415_141433_Drive.jpg
 
Hopefully the recalibration updates as outdoor air CO2 levels increase. Goes up about 20 ppm per 10 years recently, not an insignificant change over the life of an instrument.
 

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JVU said:
Hopefully the recalibration updates as outdoor air CO2 levels increase. Goes up about 20 ppm per 10 years recently, not an insignificant change over the life of an instrument.
Click to expand...
I doubt it updates over time. I don't think these are intended to be precision instruments. The listed accuracy is +-30ppm.
 
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