On or off?

I keep my thermostat set at 67 °f in the winter. So this year I purchased a mini dome light with a small 40w infrared bulb to keep tank temps up during the day. It works great. Temps are 73-74 at the top and 71-72 at the bottom. The tank usually stays around 68 if I turn it off at night.

My gecko spends her days in a hollow cork tube, but during the night she goes straight to the warmest part of the tank. She will sit there all night if I keep the infrared light on. She'll forego eating just to sit under the light. If the light is off she'll roam the tank and eat. So what do you propose I do? Leave the infrared on all night? Turn it off halfway through? Move the food to the warmest area?