Cyphastrea white spots?

[Tigerchuffs]

My cyphastrea started developing these white spots a few days ago and they have spread. Is it tissue recession or is there something else going on? Going to do a H20 change as soon as I can get the salt tomorrow but so far all my chem looks good. Any ideas?

image: https://ibb.co/DC0Tbkg

 

[blaxsun]

Maybe share your water parameters. How long have you had this coral prior to this change?