Do you know the brand of the uvb? I think the 7% ones are the esu slimline bulbs that come stock with the fixtue. If so, you need to swap out the bulb for a reptisun.
Unfortunately, the ESU 7% desert slimline puts out virtually zero UVB emissions, so you will need to upgrade your UVB light to the Reptisun 10 flourescent tube bulb. Otherwise, your dragon wont be able to absorb calcium very well & will become vulnerable to getting metabolic bone disease.
Here are a couple of links for you to compare the UVB output of the ESU & the Reptisun 10:
Unfortunately, that uvb puts out horrible uvb rays. The fixture it came with should work, but I suggest getting a reptisun 10 tube the same length as the one you have now to replace that which you now use.