I'm using all T5's 6X80 with individual reflectors. The bulbs are Geismans; 2 aquablues, 2 actinic +, 1 pure actinic, 1 mid-day. Flow is 3 Koralia 4's plus my return pump.

I'm not running carbon but do run a phosban reactor.

My params...
NH4/NH3, NO2, NO3, PO4 all not registering on the test kit.
Ca is around 400ppm
Alk around 10dKh
pH around 8.3
SG is a little low...around 1.023, but I'm slowing bringing that up with my ATO

All of my other corals are growing very well. In the month and a half that I've had corals in the tank my xenia has tripled in size, my GSP has doubled, all of my Zoa colonies have grown a few to several more polyps, I even got a green slimer, green digi, and some unknown acro that have shown good growth. Oh...and my euphillia are doing great...one is going from 3 heads to 9 plus new baby branches coming off the side...and the ScubaSteve hybrid, though not growing as fast, has picked up a couple heads. My monti's are growing...but not as fast. The favia I got a couple weeks ago is just now starting to liven up...not really any growth that I can see.

I don't know what could be causing the discoloration. It's obviously alive...but I see no polyp extension or anything.