I like the glow the reptisun 10.0 tube bulbs have and the light they produce for the tank, so I wondering if it would be possible to have too much UVB going on in a tank? Right now I have a single Reptisun 10.0 uvb 24" tube on in a 40 Breeder, and have been thinking about adding a second one (going to a 2 light fixture). This way (my thoughts) there would always be a bulb in there that is never much older then 3 months old if I stagger my bulb changing.
For instance, bulb 1 would be changed in June & December, bulb 2 would get changed in March & Sept.
I figured it was sufficient for UVB purposes, I just like the cleaner look of the light itself. Kind of a way to balance out the basking bulb light for appearances only. I just don't want to OD my little guy on too much UVB if there is such a thing.
A 24" Repti-Sun gives off enough UVB and having 2 of them, would really be too much. If you bought a fixture with 2 tubes, you could put the 2nd one in and just leave it off, just a suggestion.