bleached corals

[kb322]

I lost power for a few days so nothing was running on my tank. The temp got down into the 60's and there was a definite lack of oxygen since several of my fish died. Power is now on again but 3 SPS corals (Millepora, Acropora and Bird's nest) the bottom half is bleached (white). I've done a few water changes and now my water parameters are good. I have a 120 gallon, with 2x250W MH and 4x74 actinics. Does anyone have any advice on how to save these corals?
P.S. consider this a hard lesson learned and I will be better prepared for the next power outage.

[Hara]

you can only do what you have done and then just keep your fingers crossed. You might want to consider a shorter light schedule to re acclimate them to the light (Unless it is already too late for that).

[lando]

Two things come to mind, "shut-down reaction" (SDR) and "rapid tissue necrosis" (RTN). SDR is a rapidly progressing disease that causes the coral to die or bleach from the bottom up. It is caused by a number of acute or chronic stressors, but seems to be linked more specifically to temp. RTN is a disease very similar to SDR. The animal sheds its tissue from the bottom up. Again, caused by stressors and happens very rapidly (hours to a day). While temp can also contribute to this, it does not stand out as it does in SDR. Poor water quality (especially NO3) and sedimentation are common causes. Some say that an iodine dip using Lugol's solution can help treat these diseases. However, it will also serve to stress and already taxed animal. Recovery for SDR is better then RTN. Keep temp stable and keep up on the water changes to ensure the highest of water quality...and hope for the best. good luck.