Paly coloring question

I was given a frag of seafoam green palys about 3 weeks ago and I placed them about midway up in my tank. They have been opening up and are growing well. My question is that they are mostly brown around the rim and green in the very center. I have dimmable 120w leds (ebay) and I only have them set at about 50% white and 70% blue. would they color up more if I inrease the intensity of either light? My assumption is brown means needs more light and white means there is too much? I can post some pics when I get home, but I was just wondering what the general rule is. Also, I know that dimmable lights are good for acclimating corals, but should my goal be to get them to 100%? TIA

 

What size tank is this? and how many of the light fixtures?

 

Its a 125g tank and I have 2 fixtures over it right now. I may go the 3, but I have 2 mounds of rock right now and each light is directly over each rock formation. Here is a WTS, just hard to see the palys, they are on the left formation.