I am using a UTH hooked up to a thermostat for the hot hide but the thermostat is designed such that it has to drop a couple of degrees before it starts heating up and rises a couple of degrees above the set temperature before shutting off. I have been monitoring temps with a digital probe and the readings fluctuate between about 88 and 92 (which is the hottest I have seen it go before turning off) but I am wondering if there is any danger in the temperature fluctuating. Also I realize that since the probe is measuring the surface temp of the bottom of the tank and not the substrate the actual "in-hide" temp may be slightly lower. Can anyone out there who uses a thermostat tell me if this is a design issue with my particular thermostat or if they all work this way. If it is normal for the temperature to vary when using a thermostat I won't worry too much, I just want to be sure he is getting adequate belly heat and that it is never dropping too low. He took his first feeding last night which is why I am worried about the hide temps. Any advice would be greatly appreciated.