I've just started my first reef tank and about 3 weeks into the cycle. I am now encountering a problem. there is brown filaments growing all over everything. Its growing over my Xenia and Macro algae's. My emerald crab seems to have taken some interest but is very slow. What should I do? PS no only live animals in the tank are one Xenia, P-crab, and E-crab. the tank is 12G's so I cant add much but its been stable and is going strong. So far it isn't the biggest problem but its pretty ugly and i've had to start scrubbing it off with a tooth brush.