I may have mis-read this, but it sounds like you have the UVB on the cool side only. That's not good. Of course, get rid of the ReptiGlo, immediately, but the UVB needs to be right next to his basking spot (I, personally, have ReptiSun 10.0s that stretch the entire length of my beardies' enclosures. I don't use Megarays due to the size of my enclosures, but would take everyone elses' advice on getting one, which will change how you have to have the basking spot and UVB.)
Do you put the probe directly on the basking spot to measure the temps? If not, then please do, because you aren't getting an accurate basking temp if you're placing the probe on the side of the cage, top of the cage, etc. It needs to be where he basks specifically. If you're using a 100watt typical household bulb, I don't think it's going to heat up a huge enclosure. A 100 watt Halogen bulb might, but I'm not sure. A Megaray will raise the temps, also...so listen to everyone else on the wattage :wink: .
I apologize again if I mis-read something and for adding to the questions and didn't mean to "butt-in" on the conversation...everyone else is a little more experienced than myself, but I didn't see those two things being addressed
.
I hope he gets better soon!
Abi
---EDIT---
vickson420 addressed the probe concern of mine. Sorry!