Mar 1, 2020 #1 G Gary Ellis Well-Known Member View Badges Joined Mar 26, 2018 Messages 732 Reaction score 180 Rating - 0% 0 0 0 This is in my sump and under rocks. What is it?
Mar 1, 2020 #2 Reefing Madness Carbon Doser View Badges Staff member Super Moderator Excellence Award Hospitality Award Joined Oct 27, 2012 Messages 19,879 Reaction score 7,115 Location Peoria, AZ. Rating - 0% 0 0 0 Looks like some sponge growth.
