Stain slowly increasing over last three years of owning pool

[banjeman]

Definitely, try Vit. C and Iron Out on them.

You may want to look at this post I just made:
http://www.poolforum.com/pf2/showthr...778#post118778

I find it hard to believe it would be iron, I use city water and in the three years no pool store test has ever showed metals. The thing I wonder is I do get a lot of soil into the pool. Is there a type of staining directly related to always dealing with rain bringing in yard soil? Not sure what Etching is could that be it?