We need more information!
Size & age of tank?
Water testing data?
Why is that rock so white?
Sump, refugium, filters, skimmer, doses?
Living fish?
Clean up crew?
Water changes schedule and what kind of water?
A full picture of the tank would be very helpful.
It looks like some kind of coral war is going on... but we need the data.
Is that dry rock that has not been seeded yet?