Help - Gravel Makes Brown Spots On Glass?

[Rox]

On the front side of my tank I noticed there are small brown spots by the gravel and I'm not sure what it is. Here are pics:




There is also apparently some bacteria growing on my center decoration? I asked about it here but I still don't know if I should wash it? My understanding was that you shouldn't wash the decorations because the bacteria is good but how much is too much?


Any help is appreciated and thank you

 

[fluttermoth]

Its just a brown algae. It's common in new tanks (and on white gravel or decorations especially, I've noticed over the years). It's perfectly harmless, but wash it off you don't like the look of it.

 

[KittyKat]

Yes, those are diatoms.

 

[CrazyAirborne]

no one has mentioned it should go away after awhile.