Hollywood stunner bleaching

[jorge0912]

My Hollywood stunner one day just lost a lot of skin :( and is white all my other coral are doing fine even my other chalices why is it doing this ?

 

[jorge0912]

Here is a picture of t

 

[wesman42]

Here is a picture of t

What are all of you tank parameters currently?

All, calc, mg, phos, nitrate, and salinity/temp

 

[jorge0912]

Alk 8
Calcium 450
Nitrates 10
Salinity 1.025
Temp 79 degrees
All lps are doing fine and coral expect for him

 

[Leadfooted]

This does not look to be a chemistry problem but I may be wrong. It looks like an infection or pest.

 

[jorge0912]

I have not done a water change in a month in half so I made one and never will I skip on it again :(? Maybe it was missing something that I couldn’t read since everything had beeen okay I just thought I could get away with it :(
My mistake

 

[burnetb1]

Hard to say, has it been damaged recently? I had a stunner chalice that got a little bleached from macro algae growing over it. Even after I improved the situation the stunner continued to die.
I have had similar experiences with other coral. I have had two identical colonies in a tank and one died when the other grew. Corals are tricky sometimes.