Live in Arizona, built a 8000 gal custom pool last year. Currently have a cya level of 200, 0 fc been shocking weekly with 1 lbs chlorbrite. And running my pentair inline chlorniator on 5 with zero fc results testing weekly.
Last fall I had cya level reach 200 and 0 fc. Put in 2lbs of fresh&clear ran the pump for 5 hrs then added 2 lbs chlorbrite ran it the rest of day. Pool held a fc level of 5 all winter with the cya at 200. Only running my chlorniator at half setting.
Looking back not sure the pentair inline chlorniator was the best choice with the quick rise in cya levels. But now I'm going to either do a 3/4 or more drain and fill or if the bio-active cya reducer product is legit I will purchase it as soon as it hits the market.