I'd find somebody that has a Hanna meter and test your Po4.. If all params are fine, which your alk/ca looks fine, Nitrate of 0 if anything would make your corals look pale, but if you have Po4 in excess of about .05 you may see browning of coral. Lighting intensity plays a role too and if your lighting is not close to from where your corals came they might take a bit to adjust.