Powdery brown stuff

I have this powdery brown stuff. It looks kind of hairy and its everywhere.
All over my rocks , glass, and sand.
My nitrates are around 20 or under. I don't have a phosphate test kit.
Does anyone know what this could be? What could get rid of it?
I have a turboflotor multi sl protein skimmer a HOB filter to help with excess fish food.
I only have 2 fish, a pink and blue spotted watchman goby and a mandarain dragonet.
Both are doing great and aren't stressed. Both eating good.
I have a zoa colony, some green mushrooms and a Duncan coral .I don't see any obvious signs of stress.

 

how old is your tank?

 

Sounds like diatoms to me.

 

me too..are you using tap water?

 

I agree i think its diatoms too. You should check out this thread it is very informative about popular algae. http://www.3reef.com/forums/algae/ultimate-nuisance-algae-thread-58657.html

 

diatoms.. or red slime algae..

diatoms look more like rust particles...
red slime will get stringy once it gets out of hand.

 

The tank is about 5 months old.
I have an RO/DI unit and I have also started adding Prime by Seachem to my water just to make sure everything is taken care of.

 

could be dino's, or quite possibly some sort of blue-green cyano- which often appears as a dusty brown/blackish haze all over. Would really need a picture.
The fact that the tank is 5 months old and you've been using RO/DI water really eliminates the chances of it being diatoms, unless your getting silicates in some how.

Off topic- how long have you had the mandarin in for, and is your pod population high enough to support that in a 5 month old tank?

 

I have had him for around a month.
He has not lost any weight and is constantly grazing on pods.
I see pods all over my glass. I have chaeto in my DT to help give them breeding grounds.

 

If you have a RO DI system why add the prime ? and was this a problem before you started to add the water treatment ? It sounds like some sort of nutrient overload to me and feeding the brown fuzzy looking algae . At 5 months then it can't be Diatoms unless your filters are bad ? Do you have a TDS meter to see what the out put water quality is ?

I would tell you to stop using the Prime its doing nothing to improve your water quality and could well be causing the issue as well.