Had a huge colony of common zoas that got infected with a algae that looks like Cyano
, but is very hard and difficult to remove. It slowly chokes out the zoas. I finally did a hydrogen peroxide dip that killed the algae in seconds. Now the zoas are recovering. But I am curious as to what this algae is. Looked on all the other forums and they insisted it was calcareous, but it sure doesn't look like the pink and red calcareous algae I already grow. This stuff looks "velvety" but is very tightly attached to the rock. I looked at pieces of it that came off the rock during the dip and it seems to not have any calcium in it. It doesn't grow long filaments either.
The picture shows a tiny bit left I couldn't get at. It looks like cyano
but it doesn't blow or even scrub off.