I have a viv that is 4ft across. I have a Reptisun 10.0 mounted in the middle of the back wall. It is only 24" across so I put it in the middle. My question is it it too short and should I buy him a longer one that spans the width of the cage? I just want to make sure he is getting all the UVB he needs!
Your UVB only needs to cover about 2/3 of the tank. It is believed that bearded dragons not only thermoregulate, but also have the ability to sense when they do or do not need UVB and will move away from it as needed. Grated there is no solid proof of that, but when bearded dragons move into the shade they are getting reduced heat and also reduced UVB, so I have my tanks set up so the UVB is on the side with the bright heat bulb, and the other end of the tank that has no light also has no UVB, just like the 'shade' would be.