Thanks for info! I tried cleaning the rocks, and now that's gone, but I've gotten alot more other kinds of things growing in my aquarium. I'm not sure if its cyano, diatoms, dinos or a combination of something. I've ordered a microscope to see if I can identify what's going on exactly. Please do let me know what your thoughts are, I really appreciate all your inputs. I'm fairly new to the hobby, and I'm still learning about how to deal with all this.