This dark green material has been forming on my rocks recently, it could be a form of turf algae but it doesn’t have any algae characteristics other than being green. It feels like built up sand and scrapes off very easily. When you grind it between your fingers it’s like very light stale bread. I just hooked my ATS back up so we’ll see what happens. For now, any other ideas what this could be?
Attachments
Last edited: