Bad Bleaching

[SanFranTodd]

http://img36.photobucket.com/albums/v108/Toddman/DSC01724.jpg


I'm shocked at how fast this coral has gone downhill - went from 100% healthy to this in a little under 48hrs. Everything else in the tank is thriving, no major changes to the tank in several months. Water parameters are as follows:

SG 1.024
pH 8.0
Calc 400
Ammonia 0
Nitrate 0
Nitrite 0
Temp 80F
175w 14k MH + 55w PC actinic



I'm very frustrated - any ideas?

[MiddletonMark]

How long have you had it?
Done/changed/added anything to the tank?

[SanFranTodd]

3-4 months now - no changes to the tank

[EricHugo]

That looks like tissue loss, not bleaching, and I would strongly suggest examining closely for the small Montipora nudibranchs.