Mystery Algae

[Crustaceon]

This is the weirdest stuff. I’ve only gotten it when growing cheato. You’d think the chaeto would starve it out but for some odd reason it doesn’t. I typically have to remove the chaeto and carbon dose to get rid of it. Phosphate removers cause issues with my acros without putting the slightest dent in it. It’s almost as tough as coralline algae to remove but feels like felt on a pool table. I can in no way peel it off like turf algae. Any ideas? It’s not in the nuisance algae list as far as I can tell either. Oh yeah, and it only shows up on the back panel.

 

[Auquanut]

It's odd that it only grows on the back panel. Does the back panel get cleaned as often as the front and sides?