In the interest of increased safety, i've attatched a temperature probe directly to the substrate on top of my UTH (I use lizard liner carpet, so the probe is just stuck directly on to it). This way, I can see EXACTLY what heat my bp is feeling through the floor of his tank. My question is: what temperature should this be? I've read everywhere about specific ambient temperatures, but no where have I found a source telling me what temperature the belly heat should be held at.