Need help rock turning brown .

[Alan600]

So for the past week I been noticing the some of my LR has been turning brow and it's getting darker and darker . Does any body know what that can be ? Here's a pic of it

 

[duke4130]

Is it real live rock or man made? Looks like algae growing

 

[Alan600]

It's real live rock .

 

[Alan600]

Is there anything I can use to cure that ?

 

[ps2cho]

Its normal don't worry!

 

[IronVulture]

Snails work very well for curing that issue. The brown algae is commonly referred to as diatoms and is a normal process of your tank cycling.

 

[NanaReefer]

How old is this tank? That rock looks very well established. Personally I don't think it's diatoms at all. Have you tried blowing it off using a turkey baster?