Wacky baseline at night

• 

  mas3cf

  Posted: 14.04.2023 15:20

  Modified: 19.04.2024 19:51

  
  For the past week or so, my Aranet4 has had an issue where the baseline level creeps up slowly overnight from about 500 ppm to 700 ppm (indoors).  I know this isn't just a matter of CO2 accumulating in the house because when I bring it outside and let it equilibrate, it doesn't drop anywhere near 420 ppm - usually it stays above about 600.

  Oddly, during the daytime, it seems to fix itself.

  I have tried calibrating (3 times), gently blowing out the device with air, and removing the batteries to reset the device (a few times).

  Is this a known issue, and what else can I try?
• 

  aranet-techsupport

  Posted: 14.04.2023 15:34

  Hi mas3cf!

  Can you please confirm if physically in your device you have the Calibration set to “Manual” mode? If not, please do so and perform another calibration,

  Do you have your device connected to Aranet4 app? Please let us know which firmware version you are using and update it if possible,

  For the night-time, is it possible that you are using a heating system? Or maybe there are animals/plans near the device? And when taking it out, can you compare the CO2 reading with this page? https://earth.nullschool.net/#current/chem/surface/level/overlay=co2sc/ let us know how different it is but let it rest for 1 hour, just to be sure.
• 

  delfstrom

  Posted: 17.07.2023 01:58

  Plant respiration outdoors can often drive CO2 levels to 700 ppm and above, especially during low wind conditions, peaking just before daybreak. The amount of CO2 released at night is influenced by daily solar radiation reaching the vegetation, temperature, humidity (not too high or too low). When there is a good breeze the CO2 near the ground is more readily mixed with air higher up so it won't accumulate as much.

  You can replicate this by placing the meter on some grass one evening and covering it with a box to block out light and trap the air.
• 

  aranet-techsupport

  Posted: 17.07.2023 12:04

  Hi delfstrom,

  Thanks for this valuable addition. You are absolutely right.

  We do not usually mention that just because people rarely calibrate Aranet4 at night and rarely have so many plants at home to affect the readings.

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