Is white light necessary, and if so, how long?

[John Vinson]

From what I've researched so far, most run 10-20% white light, and the rest is blue (10-12 hours a day).  I've removed all 6 T5 bulbs (3 white, 3 blue) and replaced with 3 T5 Blue LED replacements and 1 T5 White.  The blues are the Arcadia 12W (39W replacement) bulbs, and I originally had the white also an Arcadia LED White (12W, 18000K), but it seemed too intense, so I swapped it with the T5.  I have the timer set to 8 hours and I'd prefer to go all blues (if possible), but I don't want to negatively affect the corals if I take out the white. 

If the white is absolutely necessary, what about fitting another option on the tank on a different timer, and have it only run the whites in the morning (say 2 hours), then kick the blues on the rest of the day (8-10 hours)?  I don't currently have fish and mostly have LPS's and soft corals (zoo's, GSP's, a hammer, a blasto, a toadstool, pipe organs, kenya trees, mushrooms, a cactus and a few "starter" monti caps). 

I don't have a PAR reader, so I'm considering adding membership so I can get on the list to borrow one here (if that's the best way of knowing I have the lighting dialed in).....thanks in advance for your advice!