Zigginit
Keep an eye on it the next couple days... I just changed my LED light freq a little and within two weeks Gone.. I did mount a new coral nearby.. but didn't think that would affect.... It went fast too... within two days of me first noticing a problem...
I have another SSC larger frag that is growing with polyp extension.... It started out similar brown color but now is adding green shades and the polyps add a nice contrast...