I've learned my lesson regarding regenerating purigen. It happened in my saltwater tank, after regen all my corals, especially the sorties laid down in a matter of minutes. I waited for few hours without change, and once I removed the purigen and of course did water change, they instantly opened up. What I do now, I have two purigen, one in service and the other, once soaked in bleach, I laid it outside in the sun for couple of days. I don't even use prime or other dechlorinator, bleach dissipates quickly if left out in the open, but I rinse it well before using it next time around.