I have 20 Cool Whites, 10 Neutral Whites, 20 Royal Blues, and 10 UVs over my 90, all of the LEDs are CREEs except for the UVs which are Bridgelux.
Honestly, with all the other LEDs I really can't say that I can see any visual difference between having the UVs on or off, they really don't add anything color wise, as has been said you just can't see most of what they're putting out, even on by themselves they're fairly dim. At full blast the UVs light up my tank about as much as 10 whites do on dimmest setting.
That said I've noticed a slight color difference since I added them about 3 weeks ago in some of my corals that I bought online. These corals all had pictures which showed them off as being either purple or blue but when I got them were not nearly so, partially I'm sure because I don't have them under a 20k Radium. Anyways just in the last couple weeks since I added the UVs I've noticed a slight color change in them as they've gotten slightly bluer.
I've actually been using my UVs dimmed all the way down as nightlights, I like the look a lot more than blue LEDs and my green corals seem to fluoresce even more under UVs than RBs which really sticks out since the lights are so much dimmer.
Edit: Just wanted to point out that since you're proposing a 1:1:1 ratio of NW, RB, UV LEDs you're probably going to actually see a much more significant color difference with the UVs than I do with a 3:2:1 ratio, obviously.
Edited by Elem7777, 27 January 2012 - 02:22 PM.