I started seeing some in my tank too. I threw a filter sock on and scrubbed the be-jesus out of the rock (in the tank). Few months ago my macro started dying back due to, I assume, a lack of nutrients... Maybe be got a alien strain from a passing comet
Either way it's really getting on my last nerve. I tried the "raise your Mh
to 1600 and above' rhetoric .. Not a dent..