I also use the commercial havobator but having had a spike in temperature a few seasons ago I made some changes. I now plug the Havobator into my digital thermostat that will kick the havobator off if it attempts to exceed 88 degrees. I always incubate my eggs at 84 degrees but several seasons ago the wafer failed and the temp. spiked to 120 killing all the eggs I had in it. This will never happen again or lets say should not with the double safety I now use. Good Luck--Richard

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Richard -amazoa-
"Changes in behavior occur when the pain of staying the same outweighs the pain of change."