I bought a thermometer from Walmart, the aquarium type, and put it in with the thermo that came with the 'bator. Both read totally different, so I put a digital in; one of those that reads the inside temp and the outside temp. It readers closer to the original that came with the 'bator. Frustrated I put a reptile thermo in also and it reads close to the digital and the original. I got tired of running in and out of the "chicken" room where the 'bator is so I added another thermo with inside and outside, but put the outside reader in the 'bator so I could look at the digital read out in the living room (I still run in and out of the "chicken" room!!) The thing is they ALL read one or two degrees different. I am so frustrated I have them reading right around 99 - 101 so I am hopefully in the correct range. I have all the thermos sitting on the mesh and except the original, it is sitting on top of the eggs. It is the one that reads 101. Am I doing this right. Last time I incubated eggs I didn't know much and used one thermo and never thought to worry about it not reading correctly and had a wonderful hatch, everything hatched! Sometimes I think ignorance is bliss! So I have the 1 original 2 digitals, using the outside sensor on one of them and 1 reptile thermo I threw out the aquarium thermo, it always read 10 less that everything else. So I assume it must be the truly faulty read. Also when I turn the eggs it takes hours for the 'bator to resume the proper temp. I am afraid turning eggs 3 times a day will leave the egg temp in constant flux. I try to turn as quickly as I can being very careful, but it still drops the temp quite a bit. Are the eggs possible staying closer to the correct temp and the thermos just drop more?