I'm trying this again after last month's didn't take. Last time, I was gone for a few hours and the FC dropped quite a bit while I was away, so this time, I'm staying home and checking FC once an hour. I did a regular SLAM last night, water was clear (has been the whole time), CC is 0 (also has been the whole time), and passed OCLT this morning. Brushed the whole pool yesterday and again this morning. PoolMath says my MA shock level is 19 ppm. I put in enough bleach to get there this morning, checked FC an hour later and hadn't dropped at all. Checked it again an hour later and FC had dropped to 13 ppm (pool was in almost full sun by that time). Added more bleach to get back up to 19 and am about to check it again to see how it's holding.
I'm wondering if I need to aim higher than 19 to give it room to drop if I'm losing 6 ppm in just an hour.