I have a thermometer that measures inside and outside temps. The one with the long wired probe. Anyway, I set that in the incubator to keep tabs on the temps and found that the 38.2 temp was too hot. The temps would reach 101 and 102. I adjusted the temps by this extra thermometer instead of the one that is on the lid. Some people use hygrometers but I just added a bottle of water daily and on lock down added two bottles daily and closed the little hole at the top. I keep an eye on the temp and adjust as needed. I have had great success with hatching chickens and have just hatched guineas this past week. I mark my calendar and other than the above info thats all I do.