rapid tissue loss

Hey everyone! Looking for some feedback on your success and failure rate of keeping aussie vs indo torches along with my current situation. So I have 3 tanks that all are flourishing, fairly stable parameters around 8dkh, 36ppt salinity, 77 degrees, higher nutrients (20ish nitrates) and .14...

I’ve had a reef tank for more than 30 years and have had acros for around 15 years. I’ve never seen this before. Starting about a month ago, several of my large healthy acros started turning white around their bases. Slowly, the white grows until all the coral’s tissue is gone. It started...