I built an incubator this weekend. I was lucky to have most of the parts sitting around - an Omaha Steaks cooler I got from Freecycle more than a year ago, a computer fan, and so on. I used to keep reptiles and when I raided my supplies, found I have two Repti-Pro thermostats. I used one in the incubator and I have to say it rocks as far as holding temps - it cycles on and off frequently to keep temps almost not moving on the thermometer(s). And this is the problem. I have two analog thermometers. Little round ones with a dial. I have an Acu-Rite digital thermometer, that is cool because I can put the remote sensor in the bator and keep the matching unit outside so I can read it from anywhere in the house. And I have the digital thermometer that came with the hygrometer I purchased at Wally World yesterday. Now I know there is a margin of error that is acceptable for all thermometers. But I have a greater than 5 degree discrepancy between highest and lowest and this is driving me nuts because I don't know which one to trust. The hygrometer temp reads the highest. The Acu-Rite digital reads anywhere from 5 to 5.4 degrees lower. The two analog thermometers read 2 degrees apart from one another and fall in between the two digital. I have them all sitting in the same place in the incubator. So - what do I do? If I go with one of the analog temps and set it for 99.5, the Hygrometer temp reading is 102 or more - higher than I'd like it to be IF it is reading correctly. I know that I'd rather be low than high but what if I end up too low because I'm trusting the wrong thermometer?