I've never had as good of growth as I had with Iwasaki 6.5K. That's what Sanjay uses. Of course back then I didn't know that purple corals were supposed to be purple. The yellows and browns completely washed out the purple from the actinic VHOs. 6.5K is great for a frag tank. You're better off with a good 10-12K for a reef tank though.