Originally Posted by mr_X
Either one of those I linked will make your tank and corals look very nice and grow them well. I prefer the straight blue and white ones with the white case, but many like the multicolored lights. It's up to you. I would try one first, then if you feel it's not enough, or you are getting too much shadowing on the edges, get a second.
On a side note, the white cased units have more white LEDs. The black cased ones have more blue LEDs.