I have had a metallic green trachy brain for about 6 months and has done very well until the last couple days--it started losing its color and is turning white--I have a nano cube 24 with 72 W PC lighting--All parameters in order--0, trate, trite, ammonia, calcium 440 and alk 3.4--any ideas what can be done or what's wrong--it has been feeding fine and extends as well like normal--all other corals are thriving--