Tank is 1.5 years old and I've had dkh and calcium stable for a long time now.....about a month ago, purple coralline started to start on some of the rocks - it was small amount - ie. 2-3 mm in size, but as of last week they all began to fade. I don't any inverts such as Urchins that might otherwise consume the Coralline, so I'm wondering what could be causing this?
Thanks
Thanks