Hi Alex, thank you for your detailed response. I've got a couple of noob questions, if you have time. I was wondering, what exactly is Rzero? Specifically, why can't we (instead of defining it as a fixed value) continuously retrieve the value of getRZero() or getCorrectedRZero() in real time, and use that retrieved value in the PPM calculations. Or if the Rzero is not constant over time, is that indicative of a problem in the hardware/calibration? If, after calibration, I get a constant Rzero in my living room, do I need to recalibrate it by editing the Rzero value when I move the sensor to my bedroom? Or am I misunderstanding the issue completely? I currently have 2 sensors side by side on the same breadboard, powered separately, measuring within 10 ppm of each other, is that acceptable? (These are averaged values over 30 seconds, 2 measurements per second. Are these numbers OK?) Thanks in advance for any clarification.