djp,
Actually, the hippo tang looks blue all the time under all these bulbs. The reason why it looks purple in the photos is because some blues cannot be represented with the RGB phosphors of digital cameras and monitors, so ultra violet blue ends up being protrayed as purple, which is not a true representation of the colour.
Study colour graphic design and paint to learn more about how limiting digital, and print media is! Our eyes can see far more colours than these medias can ever protray. That's one reason why origional art/paintings are worth more and are much more vibrant than any replication.
Myreef,
Well, I choose to run my tank with the Ushio since they are my favourite bulbs. The Iwasaki aren't too bad, but damn, that greenish tint sucks and I don't have the $$$$ for buying a bunch of actinics. Both of these bulbs make my corals blossom.
Hopefully when I send you that cheque for the dual chamber reactor I'll notice even more growth and better SPS colour.
-Nathan