2 pieces of advice. #1 Plumb it in with your main system if you can. IME frags just don't color up as well without the same water/nutrients etc... as the main tank. Of course I see you have it seperate now but just in case you still can. Of course if you are going to use it for QT also best to keep it seperate but IME corals just don't color up as well in seperate frag tanks (mainly speaking SPS here). #2 Use the same lighting as your main tank, same reason as #1. Frags will take much less time adjusting and changing color under the new lighting and what you get will be much more predictable. Another good idea if you are going to keep it seperate is to put a couple of fish in it assuming you have good filtration. They will help keep what the corals need in the water to keep them colored up better IME.
hth, Chris