Hey guys, I'm new to R2R but I wanted to ask a quick question about what this weird balck sea graas thats growing in a few places in my tank. Here's a picture of it. I would like to know what it is and how to get rid of it. Mind you, I run a phosban 150 with Rowa GFO. My parameters are good and I didnt have this issue before. I also just upgraded from a 28g nano cube to a 40g cube by aquatop. Thanks for helping a young reefer out!