Yes - I think you are right about the staining. Can you point me to where I can find out more about why copper sulfate is bad just so I can read more about it?

We took a sample to the store the yesterday and they said everything was good. When he called them today after coming home to the black/gray pool he asked the store what the copper reading was and they told him they didn't test the copper. I don't understand why they didn't test that! I know he put some type of algecide and shock in it last night before the drastic change. Before that it just had some dark spots on the liner, but was not completely black/gray.

What should we scrub the pool with? Will it clean the liner or will it always stay stained? Is there some place I can find out the best fix?

I really need some detailed advice, since our pool store was clueless. I promise he is going to listen now!! beleive me!!