I have the plate montipora in 12" deep tank 72W 10,000K PC, but with addition of direct sunlight. Mostly close to the top of the tank, but have one close to the bottom. Grows well close to the light. Tank is well fed (rotifer and brine shrimp eggs size food).
If you are looking for growth - in a month it should be visible.
Mine supposed to be red, but is brown. For a few months I replaced PC with 14,000K MH, same wattage. Stylopora started showing pinks, but montipora and birdsnest are still brown. Could be high nitrients problem (but NO3 and PO4 are 0).
Pinks are supposed require very high hight to keep coloration.
Here is link to detailed nano-setup description, that allows sps keep their color under the same light:
http://reefcentral.com/forums/showthread.php?s=&threadid=1297968
HTH.