Low Light Calibration Error Notice

Low light applications affected by zero-offset calibration error in some meters

On December 9, 2021, an internal Quality Control Audit determined a small number of Apogee handheld pyranometer, PAR, and ePAR meters may have shipped with a zero-value offset that was outside of our published specifications. This means some meters may not be reading within the ± 5% advertised specification when measuring low light levels. Please refer to the table and search tool below to determine if your meter is in the affected group and if you are measuring low enough light levels to be concerned.

Handheld Meter Models

Normal Specifications

Possible Low Light Error

Quantum Meters

± 5% (0-4000 umol m-2 s-1)

± >5% (0-200 umol m-2 s-1),
± 5% (200-4000 umol m-2 s-1)

ePAR Meters

± 5% (0-4000 umol m-2 s-1)

± >5% (0-200 umol m-2 s-1),
± 5% (200-4000 umol m-2 s-1)

Pyranometer Meters

± 5% (0-2000 W m-2)

± >5% (0-100 W m-2),
± 5% (100-2000 W m-2)

Please use the search tool below to enter your model and serial number to determine if your meter is from one of the affected batches. If your meter is within this affected group and you are making low-light measurements (within the error range specified above) please contact Apogee Instruments customer support by emailing techsupport@apogeeinstruments.com with questions or to request a free recalibration that will correct the issue. Sensor models not hard-wired to an Apogee meter or sensors connected to our uCache device are not affected by this error. This error was corrected and does not affect any meters produced after December 9, 2021. We regret that this quality control issue occurred and are committed to making it right for our customers. As always, Apogee believes in transparency when these rare quality control issues arise because we know the integrity of your data is critical.