So --- Michael's calculator calls for 16 lb of cya to go from 10 (we had new water last Fall and only added some closing chems) to 85. I added 9 lbs in mid April. Then I added 4lb 6oz in the a.m. on 4/22 -- buy my husband backwashed in the p.m. so I assume that was washed out. Then I added the 5lb 10 oz on 5/1. Disregarding the 4lb 6 oz that was probably washed out, the remaining 14lb 10 oz should get me to 80 ppm, right???? I will take another sample there tomorrow and see if maybe they made a mistake. I think I will just trust that I know what has been added and see how well my cl holds. Thanks very much.
PAT