Update ... I’m postponing drain/refill Or massive water exchange due to logistics of fiberglass pool. I did exchange about 10% of pool water using well makeup water and maintained balance without SWG or adding any more Chlorine for about 4 weeks. I watched the CC come down from 110ppm to about 15 ppm while FC dropped from 1 to 0.4ppm in the same period. There was also a big precipitation event in this period that coincided with the period of fastest CC decline where I lost about 400ppm of salt and filter pressure spiked, so I backwashed and recharged. After a month, I started getting sone algae around the skimmer and added another gallon on Chlorine. Within 1 day, CC shot back to 25 and FC went to 1.5 ppm. So the sulfamic is definitely still there, but pool is at least swimmable in meantime. In related news I also tried AA treatment to lift stains and it was extremely effective, I wish I had done that the first time.