I think that the biggest difference is the instead of leaning the thermo/hygro up against the back wall, i now have it laying directly on the substrate. I think that i must have been torturing this poor girl with temps that were too high all because I thought that i did not have it hot enough! I don't use the probes because Hissy gets herself tangled into the wires so I put the probes under the substrate & just use the reading I get from the unit itself. It is stabalized now because I turned the rheostat down & the temp has been in the 92-95 range all day long. It has allowed me to use the heat lamp, at a greater distance, to increase the temp on the cool side just a touch. It has stayed around 78 lately, just a couple degrees higher, but important i think. Plus, with the changes that i made, the humidity has been an average of 50 in the tank. We have 40% in the hottest spot & 60% in the coolest. She seems really happy too. Whenever she wants a little more moisture, she crawls around on the humidity mats. She is too cute!