My son is helping a neighbor with his 17,500gal. plaster SWG pool. We have been using the TF method on our pool for 2yrs. now with SUCCESS!! We used our Taylor TF-100 and got all of his values to start w/owner supplying additional phosphate value from pool store. They are dying to sell him Phosphate Free chemicals. His FC was 0 which we expected since there was algae in the pool. We inputted all of the values into Pool Calculator and have been shocking EVERY day e.g. attempting to get FC to 15ppm for almost a week now and the highest reading we have gotten is FC 2ppm with adding 6% bleach per the pool calculator every day!!!! There is still algae in the pool too. Why are we not able to get any higher reading for the FC? Son has only been testing each morning. Do we need to add more bleach than the Pool Calc. suggests? I know that the algae is consuming the chlorine, but I would think that we would have reached higher FC readings? He has been running the filter pump 24/7 and he just had all of his equipment checked. We have not gone back and re-tested other values thinking that we needed to first get the FC up and get rid of the algae and then get everything else balanced.
What are we doing wrong? HELP!!!!