Higher CO2 levels seem OK

[Art]

@Dennis Wong has a Facebook post where he measures CO2 levels up to 50 ppm with plants and fish not showing ill effect. The recommended 30 ppm that you see constantly seems to be well within limits.



So how many of you would love to have that meter?

 

[Yugang]

So how many of you would love to have that meter?

@Dennis Wong and I had some interesting discussions while he was doing his measurements, and I checked the technology of this meter. First observation is that it is really expensive, but that could be acceptable for serious hobbyists and professionals if it would bring a lot of value. A digital display always shows a "measurement" value, but that may mislead the user in that this value may not represent reality. One issue is that it takes a long time for the probe to approach the proper reading (actually quite similar to drop checkers, like up to 1 hour and dependent on a.o. flow around the probe), and that in published material the manufacturers scientists indicate that low CO2 ppm may be difficult to measure accurately.

An interesting anecdote (I hope not to sound disrespectful to Dennis because he is a great hobbyists&professional) is that Dennis confirmed with the meter the 3 ppm CO2 in degassed water that is traditionally assumed in the hobby. The problem is that from laws of physics the ppm should be at about 0.6 ppm, and only after further tweaking Dennis got closer to that is correct value. The moral of the story is that even an expensive instrument that displays 3 digits does not necessarily give the correct value - what counts is the combination of instrument, calibration, sample preparation and measurement protocol.

Before purchase, it would also be good to have critical review what can be done with the data. So design the experiment, assuming that one can accurately measure CO2 ppm, and from there what analysis would lead to what conclusions. Data are nice, but they are just numbers that do not automatically give value for the hobby. We measure 32.52 ppm CO2 in a tank, and then what?

In summary, it could be a good tool, but only for very serious/professional users with a scientific approach to measurements and experiments.

 

[Hanuman]

@Dennis Wong has a Facebook post where he measures CO2 levels up to 50 ppm with plants and fish not showing ill effect. The recommended 30 ppm that you see constantly seems to be well within limits.

Not surprised. That's what I had assumed the CO2 to be in my tanks in the past. However, this is only possible in highly/properly oxygenated tanks. At those levels the average tank keeper would have killed all his fish. In fact many people kill their fish even far below those levels due to poor oxygenation. Also, note that Dennis test was done in a shallow tank where it is far easier for O2 to be kept at higher levels hence why fish don't seem to be bothered by the CO2. I am still not sure though if mantaining fish under very high CO2 levels is healthy for them long term as in principal high CO2 levels usually lead to acidocis in fish.

 

[Art]

I agree with your comments @Hanuman. The fact that it may not kill fish in certain tanks doesn't mean that it is good for them nor that you should have it at those levels. I don't think the plants need it that high.

 

[Hanuman]

I don't think the plants need it that high.

Plants will not complain. I mean, we are merely giving them a fraction of what they would be exposed to in emersed conditions (~450 ppm). Heck even in greenhouses we pump those rooky numbers up to 1000 ppm or even 1500 ppm to increase productivity. However I suspect that under submersed conditions and higher levels of CO2, the problem will be the water, not the CO2 per say.

 

[Pepere]

Heck even in greenhouses we pump those rooky numbers up to 1000 ppm or even 1500 ppm to increase productivity.

I have an air quality meter in my house that measures CO2, CO, particulate at 2.5, radon, VOCs, temp, and humidity.

I was surprised how high CO2 levels can get in a house. While outdoor levels measure in the low 500 ppm range(Near a busy road) in living space with bedroom door left open to rest of house levels get close to 1500 ppm overnight with 1 adult respiring in house if the windows are closed and close to 3,000 ppm if bedroom door is closed.

The numbers are highest in the summertime with AC running and windows closed. In the winter with heating on, the numbers get better the colder it gets outside as air exchange increases with bigger temp differences..,

This is a structure built in 1936 and not as airtight as structures built today.

I was rather surprised how high CO2 levels will rise over night with a single person with the door closed..

 

[Hanuman]

I have an air quality meter in my house that measures CO2, CO, particulate at 2.5, radon, VOCs, temp, and humidity.

I was surprised how high CO2 levels can get in a house. While outdoor levels measure in the low 500 ppm range(Near a busy road) in living space with bedroom door left open to rest of house levels get close to 1500 ppm overnight with 1 adult respiring in house if the windows are closed and close to 3,000 ppm if bedroom door is closed.

The numbers are highest in the summertime with AC running and windows closed. In the winter with heating on, the numbers get better the colder it gets outside as air exchange increases with bigger temp differences..,

This is a structure built in 1936 and not as airtight as structures built today.

I was rather surprised how high CO2 levels will rise over night with a single person with the door closed..

Indeed. I do have a CO2 meter as well at home. Breathing high levels of CO2 for a prolonged period is unhealthy and hinders brain function. I leave my bedroom door slightly open at night to allow CO2 to evacuate.

 

[Pepere]

I do have a CO2 meter as well at home. Breathing high levels of CO2 for a prolonged period is unhealthy and hinders brain function. I leave my bedroom door slightly open at night to allow CO2 to evacuate.

Interestingly, and perhaps a tad concerning…. The US nuclear Submarine fleet works to keep ambient CO2 levels on submarines under 4,000 ppm.

I too sleep with my door open to the rest of the house to keep levels below 1500 ppm. My preference would be to keep levels below 1,000 ppm but that would require air exchange with an energy recovery ventilator when air conditioning..,

In the middle of winter when it is below the 20s outside, I see co2 levels of around 800 ppm…

If you have a meter with data logging over time you can use the clearance of co2 from the living space over time with no one in there to calculate what your air exchange rate is. I did the calcs and find it changes significantly with outside temps.

My air exchange during 40 and below are within recommendations…

 

[*Ci*]

We did some bathroom renovations recently and found the new building code regulations where I live stipulate 24hr., “always on” ventilation, meaning a fan that has no wall switch - it is always running. So that is what we had installed (our old bathroom fan was venting right into the attic!). We were sceptical at first but the unit is very quiet on low and switches to high with a motion sensor when someone enters the bathroom.
The installer said it would lower co2 levels and logic dictates that it must be so, but I don’t have a meter to test it. They also assured us that it would not impact our heating bills in winter. We shall see …
My house was built in the 40’s with no lack of unintended ventilation (lol!), I keep the bedroom and bathroom doors open all the time, no air conditioning. Might be worth consideration for those worried about elevated co2 in the living space.

 

[Art]

Interesting and concerning discussion. I don't have a CO2 meter to check indoor levels. However, I live in a location where houses are heavily insulated to maintain air conditioning in the home. I can only imagine how high CO2 levels get...

 

[Hanuman]

Interesting and concerning discussion. I don't have a CO2 meter to check indoor levels. However, I live in a location where houses are heavily insulated to maintain air conditioning in the home. I can only imagine how high CO2 levels get...

I highly advice you aerate your house and bedroom. CO2 at high levels is really unhealthy if breathed for prolonged periods.
This is in my living room, last 90 days. When I used to have the meter in my bedroom with closed doors at night it would go up to ~1800/2000ppm. After I opened the door it would drop to ~900ppm.

 

[Art]

Gees! I'm going to have to buy a tester because now I'm curious/concerned. What tester do you guys use?

 

[Pepere]

Gees! I'm going to have to buy a tester because now I'm curious/concerned. What tester do you guys use?

I use the Airthings View.




https://www.amazon.com/Airthings-29...-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

 

[Hanuman]

Gees! I'm going to have to buy a tester because now I'm curious/concerned. What tester do you guys use?

These CO2/pm 2.5 etc meters can get quite expensive but there is one option. Airgradient.

I have an old model which was DIY and I had to solder all components myself. I only paid 96USD at that time. Now they are selling a pre-soldered and upgraded version but you have to assemble it (pretty easy honestly) and it goes for 138USD or you can get the fully assembled version for 195USD. The pre-soldered version I think you probably need to upload the code yourself onto the board with the Arduino app. Airgradient makes the code available on their Github repository. Really not that difficult.

If you go for ready to use CO2/pm2.5 meters they will cost you a ball. Probably no less than 250 USD at best (like the one posted by @Pepere above). DO NOT, I repeat, DO NOT get fooled by those cheap CO2 meters you will find if you google "CO2 meters". Those use either a TVOC sensor or a very cheap NDIR sensors which are highly inaccurate. To quote myself what I wrote in UKAPS 2 years ago:

Be aware that those are not real CO2 detectors. They are actually extremely inaccurate and use a simple and cheap TVOC sensor which by design and specification are not meant to detect CO2 or measure in any way CO2 since they only output one signal. CO2 concentration is then extrapolated, calculated and faked through a chip. Proper CO2 detectors use what we call an NDIR CO2 sensors (nondispersive infrared sensor) which by themself are pricy. The component alone will cost ~30/40USD sometimes more depending the manufacturer. So any CO2 monitor out there retailing for less than 100/150USD or less will just be a scam and you can be warrantied that what you see on the screen of your cheap Chinese made device is no where close to the real concentration of CO2 in the air at any given time of measurement.

[...] el cheapo NDIR sensors like the one you just referred to are basically copies. Aliexperess is flooded by them. They are slow, inaccurate, unreliable. They usually have a detection range of 400-10000ppm or 0-5000ppm which technically is fine BUT with a very poor accuracy which can range from 100ppm to a 1000ppm . There are not many companies producing quality NDIR. I suggest looking for Sensirion, Winsen, Cubic, Senseair. All produce quality, reliable sensors. Some are very expensive some very reasonable [...]

The reason Airgradient is able to make it cheaper than anyone else is because you have to do part of the work (assembling the monitor) and uploading the code and configuring the meter. Code is open source as well so you can customized it at will if you know about code, else vanilla code will work fine.

When I used to have the meter in my bedroom with closed doors at night it would go up to ~1800/2000ppm. After I opened the door it would drop to ~900ppm.

Actually I looked back at the posts I made on UKPAS. I was slightly off. CO2 peaked at 2500PPM during the night when doors where closed . I found an old screenshot:

Anything above 2000ppm is really not healthy. In fact anything above 1500ppm you should already be taking action to reduce it.

Also keep in mind that CO2 is denser than air so it will accumulate on the ground first then build its way up the more CO2 is introduced in the space. So technically making a large enough hole on the floor would work too

 

[Art]

Wow, thanks. That is a lot.

Making a note to do some research this weekend to purchase something. It's good to know what NOT to buy. I appreciate that.

 

[Pepere]

Airthings has a website with good information about home air quality. I think it is a worthwhile read..

Airthings Blog - Resources, Research & News on Radon Gas - Get it Here!

Airthings resources, research & news covers all things indoor air quality including radon gas, volatile organic compounds (VOCs), carbon dioxide, humidity, temperature and more!

www.airthings.com

I have been happy with my airthings View. I like that it monitors Co2, CO, radon, pm 2.5 pm 1, VOCs,, temp and humidity and logs the data over time. I also like the real time alerts it sends to your tablet or phone when levels of one or more exceeds recommended parameters…

I found it quite surprising to learn how much Particumalte Matter spikes when frying…. Make popcorn on the stovetop with oil. Oh My! Make sure you have windows open and a fan or range hood… or have a good sized Hepa filtration unit… or 2 or 3…. VOCs up? And not going down? When did you change the carbon prefilters last….