Unfortunately, I didn't buy the dimmer option with my fixtures, beginning to think that was a mistake. So what I've done is placed a mini colony of my red planet further down in tank and in different side to see if it improves. The mother colony is really the only coral that is brown. In fact, most of my coral have improved in color. Now, I recently read a thread about too much flow for Red Planets. I do have mine about 2 ft. away from my mp40, but it is in direct line, could this be the cause for the browning, and not the lights?