Gravel color

[bhath19]

My white gravel has been turning like a rust color, is this normal? I think it may be b/c I got it at Walmart, haha.

 

[Corty]

Sounds like algae to me.

 

[QTOFFER]

Diatom 'algae' to be specific.
Try getting a few otos. They love tp eat the stuff.