I built a homemade incubator from plans on byc. I took a cooler cut a hole in the top for glass to see inside two holes in the sides for ventilation a light bulb inside connected to a hot water thermostat along with a computer fan a plastic dish for water and a hydrometer/thermometer combo. Works great able to keep a pretty steady humidity % but the temp is another thing. The hydrometer/ thermometer tells me the high and low for the past few hrs. Well it started off going from 102 to 95 now I have it set so the high is 100 and low is 88. This is my first incubator and my first time incubating pretty sure from the people I've talked to and things I've read that wont hatch eggs. Any ideas on how I can get my temp more steady?