Definitely cyano. Corraline is hard and doesn't bubble. If cyano is left to grow for a little while it will become long and stringy.
How old is the tank and give us some test results.
ChemiClean is a good product to remove it, but caution should be used. If your tank is new and has no livestock I would try to remove as much as I can and work on exporting those nutrients. Water changes, media reactors with GFO/Bio Pellets, and frequent filter changes.