How long does metal sequestration take?

[Centex Newbie]

Hi, folks. I have a new Intex pool that I filled with municipal -- but hard -- water. Once I got the chlorine going (via SWCG), the water turned brown. I dosed it yesterday with a "stain and scale" remover but it's still brown. I remember reading somewhere that it takes a little while, but I can't find that reference any more. Just wondering when I should give up on that method and try some other type of way of dealing with the hard water.

Any tips welcome. Thanks!