Question about heat tape and incubators

I have my incubator setup just incase my girl is pregnant. So my questions are where do you put the probe for the thermostat in the incubator? I have mine on the bottom of the cooler under the water bottles taped to the top of the heat tape. And what temp do you have to set the thermostat at to get the right temps in the egg box? I have a thermoter in the egg box. I am doing water in the bottom of the egg box with egg crate to keep the eggs off the water. I can't find vermiculite or anything in my area that doesn't have chemicals in it. Right now with the thermostat set at 98, the egg box air temps are sitting at 86. I don't know how hot is to hot for the cooler. And the range that the egg box is suppose to sit at is between 88 and 89 degrees right? Thanks for any help.

hey there check out stirctly balls. Mykee has a great incubator diy. i got my vermiculite at walmart they also had perlite if you want to do a mix. I taped my thermostat probe to the top of the incubator with 4/5 inches hanging down. I have my herpstat set at 87 to get 89.5 in my egg boxes. Good luck and hope you get lots of eggs.