Hello Jacqui,
You know that you can PM me anytime, ok? I am not too busy for you.
You have gotten great advice. This is somewhat of a hard case.
I have double checked the data on this light, & since you are using the 160watt, this particular wattage for whatever reason, has not caused any problems that I am aware of right now. The Powersun 100watt is the culprit, due to a manufacturer's fault of having too thin of phosphorus coating on the inside of the lamp face. That was what had caused the eye problem with the 100watt, too strong of UVB at that recommended distance with leakage of possible UVC & the UV index was higher at that distance than it was at the same distance with the 160 watt.
Having said that, I am pretty confident that is it not your bulb. It should be good for at least 10 months, possibly 1 year. Now, bear in mind that it is not as good as the Megaray or the T-rex by any means, but, it IS sufficient enough to provide adequate UVB exposure. The UVB readings per Frances' UVB meter testing did show in November 2008, that it was 90uW/cm2 with a UV index of 5.4 @ a distance of 12 inches. I have no reason to believe that they have altered the Powersun 160 watt bulb since there have been no reported problems thus far with them.
The only things that I can think of that could be causing this type of problem would be a nutritional deficiency or imbalance, the inability for her to absorb calcium for metabolic reasons, etc, or you have a faulty bulb. The calcium that you use, is it plain or does it have the added D3 to it?
If it has D3 in it then, you will need to cut that supplement out & just use plain calcium. They can get "hypervitaminosis D" from excessive D3 supplementation. What type of greens are you feeding her?
How do her urates look right now? Are they hard, off colored, or soft & white?
Are you noticing any other problems such as deviations in the tail, etc?
In any case, it might be a good idea to consider switching to liquid calcium for awhile, just in case she is having trouble absorbing the powdered calcium for some reason. There are quite a few reports on dragons who have some trouble absorbing the powdered calcium.
Tracie