Oh man thanks... It's stringy/fuzzy. I just replaced the floss and I'm going to take some water in to have it checked anyway. I have a Lunar wrasse that will seek and destroy anything that is small and crawls. The algae will stick to the rocks, but it is all over my crushed coral and glass. It's not real easy to get off, but will come off with my magnet scraper if I keep up with it. I've been in and out of town trying to get a job, so when I got back it was pretty bad.