Ah, hadn't thought of adding eggs! I did install a fan and put the water in. The temp still swung a bit, from 102 to 96. It is a very thick walled cooler so when the light does shut off, it holds the temp for a long time. Its a 40 watt light bulb and the cooler is 20" wide by 12" deep. I did read about someone who drilled holes in the their thermostat which helped the swing as it let the air in to the needle, but mine didn't have screws so I would have to pry the whole back off and was afraid of breaking it. I did open up the back a bit with a screwdriver. I tried facing the fan so it blew right at the thermostat, but that didn't help much either. The only other thing I can think to try is to put enough holes in the cooler so that it stablizes right at 100. Luckily, the eggs (turkey) are a day late, of course, with it being 95 yesterday, god only knows where they sat all day yesterday and if they even will hatch at this point. I am going to put a few chicken eggs in a few days later to try to get a hatch on the same day, as I have had turkey poults before that seemed not to figure out how to eat. This is my first attempt at incubating myself, I already used up all my broody hens!