I just upgraded your membership, and since you included your address (which results in a higher user privilege level), I looked up the address on Google and Bing. (I'm the only one that can see that info -- none of the moderators have that access.)

Anyhow, given your location, it's unlikely you are on well water, so a major question you need to answer is, "What kind of metal is staining your pool, and where did it come from?". If it's iron, old city water lines are a possibility, but if it's copper, you need to figure out if it was from algaecide use, an eroding pool heater, or something else.

It doesn't do lots of good to remove stains, unless you also make a plan to avoid the situation that created them in the first place.