Just thought I'd post an update on my 'bator build. I got tired of fussing with a water heater thermostat and decided to put on a Ranco. The thermostat was always off just a little too high or a little too low (the one in my cooler 'bator is working fine, however). So I bought a Ranco, which is widely used in reptile setups. Pros: - You can set the temperature you want - I set mine to click off at 100F - You can set the differential you want - mine is set for 2 degrees. So when the temperature drops two degrees, it clicks on (seems to come on when it hits 98.9) - It has a built in probe that you can put directly in your water wiggler - You can wire the thermostat to control a power strip and just plug your light into the strip - You can later move the thermostat to your brooder if you want and let it keep your brooder the correct temperature - Shouldn't have any temperature spikes (this was a big deal for me) Cons: - They are expensive (~$55 w/ shipping) - You have to wire them yourself - The are big I bought a second one that will be for my brooder setup, that will keep the light from getting the brooder too hot or too cold. And because I wire mine to a power strip, I can run it using two lights, in case one burns out. Here's a pic of the thermostat. That black powerstrip is wired into it. There are good instructions on the net for wiring these things up. The probe is set in my home-made wiggler - I put a green circle around it in this picture. The wiggler temperature is holding extremely well, as measured by the second wiggler with the Thermoworks thermometer.