What the heck?!??

[austenreefer]

This is a 2 day difference between these pictures. What happened?! Just tested the tank:

Calcium: 450
KH: 9.9
Mag: 1320
Nitrates: Barley at 1

All the other coral look completely normal.... could it be my peppermint shrimp?

 

[Acrofiend]

High alk and low nutrients= death.
Lower your alk under 8 and it’ll recover.