You can add a bunch of chlorine and raise the pH, and you will tend to form the precipitate. Usually, this can be vacuumed up.

Or, you can raise the pH, and add chlorine via the skimmer, which tends to bring the iron out on the filter, partly as stain but also as filterable gook.

Before we get started, however, we've got to be sure you have control of your pool. The polyquat and metal stain product are just 'buying time' till then. You need a K2006 or K2006C (sig link for Amazon purchase), and we need test results + a description of your pool, pump, & filter. Also, the ideal way to remove the iron requires cal hypo (not copper filled goo, though a cal hypo / borate mix is OK, if overpriced) AND complete removal of any sort of feeder, tabs, mineral product or other stuff that may be ANYWHERE from the skimmer / drain to the pump, to the filter, & back to the pool.

Ben