What’s this stuff growing?

[ondy6611]

It doesn’t come off when I take the cave and silicone anemone out to clean. Coralline?

 

[ondy6611]

 

[EnterName]

Cotton Candy Algae like Callithamnion sp. or Asparagopsis taxiformis (sporophyte phase)?

Cyanos would come off quite easily, are forming mats, not turfs (besides Lyngbya maybe, but that looks more like hair algae) and Cyanos are usually darker/purple.

You can find some info on Cotton Candy Algae here: https://www.reefcleaners.org/nuisance-algae-id-guide