Hi- this is probably a silly question, but do I need to calibrate a digital thermometer/hygrometer? Do I use the "baggie of salt" method that I use the non-digitals? Mine is this one.... I just hope I can trust the numbers-. I had another brand that I got from a friend used. It was off by about 10 degrees and humidity percent- and I lost the whole group. Thanks! Pam UPDATE- I found my answer! I do.