I replaced the resin in my softener a month ago. Everything was fine until a few days ago where the same problems I had crept back up. Standing water in a toilet bowl would turn yellow which tells me it is clear water iron. I sprinkled some iron out powder into the bowl and the water in the bowl cleared up. Is it possible that my brand new resin already fouled? My unit was backwashing every 1600 gallons. I did not add res care or anything to the brine well so it has only been using salt.