Most color loss is due to poor water quality and lighting, pest such as flat worms just find their way up your coral and block light from hitting the spot of the coral they attach themselves to, leaving just a bunch of spots in the shape of themselves on your sps.. Reguardless you should always dip your coral no matter where you got it.Be extra careful buying the brown stuff. Loss of color can be due to bugs/worms, not just poor light and water quality.