Surprising result. SLAMed the pool to 20 FC (from 3, added 17 with 1 gal, 1 qt, 2 cups). Checked an hour and a half later, was down to 16.5. Doing this after dark (how do people SLAM in the daylight and account for the light eating the FC?). Just added 3.5 more, going to check in an hour or so before bed.
Stunned it lost anything. Every day it was losing about 3 and water was clear, that did not stir up any suspicions on my part
As i said, i am SLAMing for a 50 CYA even though i am pretty sure i am lower than that-but i assume i can go as high as i want with FC at night-even if i put 100 FC in it (i won't) it shouldnt lose any at night, right?