Howdy,
Jeremy is right about temperatures. Either use a dedicated wire external probe type thermometer ($10-$20) and/or get a
http://www.tempgun.com/order.html#pe2 PE-2 Temp Gun $45 for measuring, among other things, the actual skin/body temperature when measured between about 0" to 8" away from the chameleon.
Part of figuring out what is "wrong" with a chameleon is eliminating as many things that have been known to create problems in the past with other keepers. One of the things that you are trying to do is reduce what stresses-out your chameleon. It may be discovered that what was a problem with one keeper's chameleon isn't a problem or doesn't bother your chameleon. BUT eliminating as many of these things is what offers the best chance of ending-up with a healthy, stress-free critter.
Potential issues:
It looks like you are using an ESU fluorescent tube and fixture. Did you remove the plastic lens? Don't feel bad if you didn't. We, of the UVB_Meter_Owners Group, "beat-up" the mfgr about this lens and its filtering of ALL of the healthful UVB thus leading to the slow, painful death of many a chameleon. They are looking into providing a type of screen cover for the tube. If you still have the lens in place, just unscrew the two screws holding the clear plastic cover and remove it (just like the rest of us do!)
When you feel that you have $14-$20 available, replace that tube with a Reptisun 5.0 tube made by ZooMed. (Online pricing as low as $14 per tube.)
I am familiar with your type of enclosure. 90% of successful USA chameleon keepers will recommend that you not use any substrate on the floor of the enclosure. This allows for all of the water that is dripped and misted (easily a quart per day) to be drained out through small drain holes eliminating the potential for dangerous bacteria build-up. Your situation is complicated by the fact that you have a glass bottom. If you want to follow what works for most people, with buy a new screen enclosure that has a PVC bottom that you can drill and let the dirty water drain into a catch pan. You can also bust-out the glass bottom and insert a PVC (plastic...) bottom that can also be drilled with many ~1/8" holes. I've actually busted out glass from those exact same enclosures (tough glass!) helping a friend modify his enclosures for "full misting".
Your chameleon needs to be able to get within 6"-12" of the UVB source otherwise the UVB effect will be minimal - not good. Your 75W heat source is likely to be sufficient when positioned to meet the basking temperature spot. You may find that you need to raise it above the screen top to get the temps set properly.
Look into adding some live plants. Try Ficus and Dwarf Schefflera. Raise them at least 1" off the bottom to allow for proper drainage and floor drying. Many chameleons seek out dense plantings for a sense of security. Less stress! Add more climbing structures that are smaller diameter for full grasping. The live will fix a lot of that but also add things that are about the diameter of a pencil too.
Chameleons are often more comfortable looking down at their keepers, so if you are able to raise the enclosure, the higher the better! Less stress!
Glass sides have been found to stress-out some chameleons from seeing their reflection. Put your chameleon in front of a mirror once to see the effect. Also chams have had tongue injuries trying to shoot flies on the outside of the glass!
That's it for now...
Oh, an old photo of my setup as what I mean about plants. These are 24x24x48 enclosures at about $100-$150 each.
Dave Weldon
