Need help - Brown Caramel-color problem

[stingrae]

Have had brown caramel-color covering live rock & sand. Tank parameters: Nitrate - 0 PPM
Nitrite - 0 PPM
Ammonia - 0 PPM
Ph - 8.4
Phosphate - 0.5

55-gal. main tank has 30-gal. skimmer & refuge tank. Skimmer (ETSS Reef Devil) run by Eheim 1262 (900 gal.) Also, 15-gal. wet/dry filter with Mag-7
return pump. Can't figure out what to do to eliminate brown problem. Any help would be appreciated!

 

[JayM]

Is your tank new?

Do a search for diatoms.

A phosban reactor may help you get your phosphates to zero. New tanks go through a diatom phase, but they will go away with time, patience and water changes.

 

[Greg Hiller]

Are we talking about a thin coating of brown on stuff, or snotty type brown stringy stuff? The former is diatoms (rarely a problem for more than the first week or two) the latter may be dinoflagellates (dinos), more of a problem, but also usually transitory.