purple live rocks turning green

Hello everyone on TRT.. I am 7 days into a new cycle and My purple coraline covered hand selected live rock is turning green? The rocks are turning the green color only were the rocks are exposed to the most light and what ever is left of the coraline algea is turning darker in color. Any ideas? PH is around 8.0
,ammonia 0 ,nitrites 0, and nitrates 0. I have been feeding the system with high protein flakes adding slightly more everyday along with adding seachem's aquavitro seed daily.