brownish algae looking growth stopping polyps?

[houstonreefer20]

Hello all,

I have a beautiful zoa colony which I've had for a few months, 100+ heads. Recently, I've noticed a good chunk of the zoa heads have stopped opening. Upon closer inspection, I've noticed some sort of growth has been ontop of the colony.

Take a look at the attached picture. Anyone have any idea what this is? How can I stop/fix the issue? I've tried blowing it with a turkey baster and also putting powerheads on it, with no luck :hmm2::thumbdown

 

[houstonreefer20]

Anyone?

 

[Go.Fish]

Had something like this for a while affecting a bunch of zoa colonies. Treated the tank with Chemiclean as per directions and it fixed the problem. Something for you to look into? Try searching for "brown dust"