I am using ortex algae pool shock...68% calcium hypochlorite (provides 68% available chlorine)...
doubt it was the dupont treatment....as I was exclusively adding bleach when the stains showed up (stains showed up same day pool co had added the alk and CYA, coincidence???)..

i had grabbed the dupont thinking it was shock...only after I had drained the pool and refilled it...meaning within the last few days...