Feb 22, 2018 #1 GK3 Valuable Member View Badges Joined Jan 16, 2017 Messages 1,852 Reaction score 1,339 Location Cincinnati Rating - 100% 2 0 0 Anyone know what this is? It’s slimy, not hard like coraline.
Feb 23, 2018 #2 NanoCrazed Well-Known Member View Badges Reef Tank 365 Joined May 30, 2017 Messages 617 Reaction score 2,463 Rating - 0% 0 0 0 Hard to tell in photo but if it darkish red/brown, it's likely cyano