Black gravel turning brown!!!

[aerofish]

I know there is algae in my tank. I see greenforming on the rocks. But I recently noticed a golden/brownish coating on my gravel that is supposed to be completely black.


What's more mysterious is that it's only forming on one little section of the gravel. The other parts are still black. What is this and how do i fix it b4 it gets outta control??

Is there a fish that takes care of this? Any chemicals???

 

[AquaSeaFoam]

Do you have a gravel vac? sounds like it might just be the fish poop settling on the gravel..
If so, no fish or shrimp will eat poop. And it is generally best NOT to add chemicals to a tank.
Could also be brown algae which is actually diatoms. do a search on google and see if you can get a picture.