Help! Brown Blanket Like Substance

[RMD_4]

I am in need of some help identifying what’s going on in my tank so I can fix it ASAP! I have noticed this thick brown film that started blanketing my frag racks and plugs in my tank. Now I’m noticing it on my power heads and rock work. It’s not smothering my corals (yet), but it does not look appealing to the eye at all. It has to be scrubbed off, it doesn’t appear to be fazed by basting water on it. I have attached a picture of it on one of my racks so you can see what I am trying to describe. Hopefully someone can shed light on this! Thanks.

 

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BUMP

 

[ScottB]

Good news is that is not likely to be dinoflagellates. Nor chrysophytes. They baste easily.

Sounds like some kind of algae. They come in all shapes and colors.