Has anybody tried to use heat blankets or any large scale heat sources inside the cage? It seems that would bring up the ambient temp and add a good amount of heat to the basking spot. My gu's cage has a 150 watt mercury vapor and a 100 watt basking bulb, and a 65 or 70 watt nighttime bulb, but it still seems a little cold. The cage dimensions are 5'x2'x2'. The lights sit around 1' 8'' above the basking spot. Let me know what you all think.