The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Water parameters are checked and weekly water changes. I skipped one time this year. It's not on the rocks and no red hair. Is it a different type of coralline?
If it is hard and not hairy then I'd say it is a type of coraline. If it is hairy I'd be concerned that it could be cotton candy algae, something I've personally battled for a long time in my system.