Hi Todd, don't know this specific product so can't comment in too much specific detail.
A dechlor agent will neutralise any active PP turning brown. I normally use hydrogen peroxide (H2O2) to do this, as it leaves the water crystal clear. Add the H2O2 very slowly, a few drops at a time and give each dose a few mins to work.
And again when I do PP bath I do a minimum of 4 hours and I dose at 2ppm, and never do I (deliberately) go above 4ppm.
So basically I dose the PP, wait the 4+ hours, neutralise then do a water change. hth.