Please can someone identify the white area

[DiscusZ]

I am trying to find out what these whitish areas on one of my live rocks. this rock was devastated in Late july from a tank over heating due to extreme hot weather for a long period of time. (I was on holidays and someone was looking after my house)

Anyways this rock used to be covered in coraline algae. I noticed the other nite this white area, when all I had on was the actinic lights

They do not move, been in the same spot for 2 days now. I am assuming its some sort of invert

Thanks for the help in advance.


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Picture #2




Jim