Temps are very important, but they just might be starting the cool down cycle. They will prefer the cool side and not eat. I like to take a digital thermometer with a probe and tape the probe right on the inside of the tub over the heating element where the snake hides. I like the ones that read inside (the thermometer itself) and outside (the probe). Then I tape the themometer to the front of the tub (coolside) so I can see it at a glance. You'll see the cool and hot temps and also they come with high and low memories so you can check whats going on and adjust as needed. I think it takes out all the guess work. Then you know if temps are a factor. Some come with humidity reading too. Home depot or OSH will have them cheap.