Need Help Identifying

[Imhotep75]

can somebody please tell what this is? this brown junk and how to get rid of it. It is driving me mad i just increased the flow of the tank and am changing the mh bulb right now

[cloak]

Check this out.

http://reefkeeping.com/issues/2006-11/rhf/index.php

[Imhotep75]

well thanks a bunch