This is what I am going to put in my Incubator once my hatch is done. What i may do is have it turn off and on a small fan forced heater instead of a light bulb. The water heater thermostat fluctuates too much.
http://www.ebay.com/itm/PID-Digital...629?pt=LH_DefaultDomain_0&hash=item3a6fd1d8a5
http://www.ebay.com/itm/PID-Digital...629?pt=LH_DefaultDomain_0&hash=item3a6fd1d8a5