Wondering out loud.

[christyf5]

I was thinking more that perhaps you have more fauna in your sandbed that might have died off creating the problems. I don't know if I've ever treated with interceptor with a sandbed as previously I didn't seem to be able to keep SPS with a sandbed.

I have various patches of cyano that only occur on the rocks although when I had dinos they weren't picky about where they grew. I do find it odd, how the dinos (or whatever algae you showed in the photos) are growing on the little dead bits of some of your corals that are still living. Have you tried breaking those bits off? I suppose inevitably you would always have a bit of skeleton exposed that way.