Review on 🌱 Rechargeable Formaldehyde Monitoring for Temperature Control in Nurseries by Christopher Clearfield

UPDATE: After a few weeks of use and finding a very informative calibration, the calibration has drifted wide with outside readings around 860 (instead of 405 -430 which I received when it was new). Since I can't start the calibration mode after following the instructions, I can't fix it. It was fun while it lasted, but I encourage you to buy another one. ALT: Looks like it works by going from room to room and outside. But I can't enter the calibration mode I want to use. The instructions say to press the a and b buttons together to start the calibration and the 200 second countdown, but nothing happens. Anyone have a calibration? Thanks very much!