We don't just provide them with light, there's a UTH on the warm spot of each tank.
I just found out a little ago the thermometer he had wasn't the right type, but now I got a digital one and it seems to work fine.
I think what's been happening is that there's been too much light, and that's been affecting the humidity. The old thermometer wasn't the right kind, at it said the temp was way too low. Now, though, that we have the digital one, the temp is actually a lot higher than we thought.
I think we just had too much light, and combined with the UTH it was too much heat and that wasn't too great for them.
Thanks guys.