Stylo problem

[Maho.B]

Hello. I have a purple Stylophora that has been doing great for over a year. Bought it as a single stem frag and has grown pretty well and always great color and PE. As of a few days ago, there are bare white areas randomly on it, where there are no polyps, just bare white skeleton and the PE over all isn't great. No new fish or inverts have been added. A little over a week ago we lost power for about 12 hours, other than that nothing parameter wise has changed and all other corals like Acro's, Monti's, Pavona, Psammocora, Porites, and a mix of LPS are all doing great. Any thoughts as to why a Stylo would suddenly lose polyps in areas? Fish in the system are:

Pair of clowns
Royal Gramma
Tailspot Blenny
Geometric pygmy hawk
Mandarin
Hectors goby

It doesn't seem like one of those would all of a sudden do anything to it. I also have peppermint shrimp, emerald crabs and assorted snails/blue legged hermits that have all been in there for awhile. Thoughts?

 

[Rocks reef]

Did you experience a large temperature swing during the power outage? Were you using any sort of battery backup to provide some type of water flow for surface agitation to aid in oxygen exchange?

 

[Maho.B]

Unfortunately my EcoTech battery backup did absolutely nothing so it must be installed incorrectly which I'm looking into. There was no water movement for 12 hours during the power outage. The temp went down from 78 to 74 during that time. With no other changes other than the power outage, I assume the Stylo is reacting poorly because of it, I am just surprised the more sensitive SPS are not. Thanks