Hello,
OH so you have a Zilla T8 tube bulb? That is a high possibility the zilla light is causing some eye strain for
him. I would use just the Reptisun T5 alone along with the basking light you have now. Since you don't
have a screen top, you can place it at 12 or so inches, which will give him excellent coverage & UVB exposure.
How is he doing today?
I did have a zilla bulb in the fixture for a little while but then replaced it with a Reptisun T8. So I have a T5 covering the majority of the tank and a T8 on the side resting where he usually likes to bask. Could the zilla FITURE be causing the problem, not the bulb? He must just be a rather lethargic beardie. He's eating and seems perfectly health, aside for some stress marks on his belly. He still has his eyes closed the majority of the time and doesn't move much.