27,500 gal chlorine pool opened one week. CyA is now 19. Can't get a FC level. They keep having me shock but no results. Last shock was 12 lbs. I have been pool owner for 19 years don't know what else to try. We have now added 25 lbs total. Pool is clear, ph 7.2, alkalinity 128ppm, TC 3.98 but no FC. Tired of dumping money! Any thoughts?