Best Kelvin for reef lighting

[marcingo]

I am setting up a 55 gallon (4ft x 1 ft wide x 21 inches tall) and I am planning on using 2 250 watt metal halide bulbs. Basically I would like to know what everyone thinks would be the best lighting for both coral growth and aesthetics. Also I would like the corals so show their colors the best in the chosen lighting.

I realize there are a few different type of metal hallide bulb kelvin and have learned that 20k is the bluest. I find I like the look of a tank with a blueish tinge to it. But I have also heard that 6500k is the best for coral growth. I dont really want to add a whole setup of actinic bulbs. I did buy a power compact 24 inch light for my 10 gal nano(that recently crashed) that I could use for the actinic on one side of the tank (is it possible to just replace the power compact daylight bulb with a actinic bulb?) But other than that I do not want to add any VHO or other flourescent lighting when I set up the MH because I plan to have them in a pendant. If I place any flourescent lighting (Actinic) on the tank it will be in the way of the MH light coming down from the pendent.

Anyway sorry for the long digression but what once again what is the best lighting for me. I would like the bluest possible that still has reasonable coral growth should I go with 14k lighting, 10k or just stay with the 20k that I have been planning.

Thanks