cyano

All my parameters seem fine, water changes have been occurring like normal, I seem to have what I can only describe as rolling death. It started in on tiny area of my tank I noticed a few of my blue clove polyps not opening up and that was about 4 days ago. Now it has spread out to about a 8-10 inch area and claimed my only acropora that was finally starting to show new signs of life yesterday it was fine and that area was untouched and today the acro is nothing but skeleton and the area continues ...