After the sun is off the pool, test FC and plug that number into pool calculator, then add enough bleach to bring FC back to shock level (12). Then wait an hour, test the actual FC level. Use that number as the start for your OCLT.KGK said:Yes...I am curious. If I bring it to shock level tonight, when do I test it (tonight after adding bleach) so I know an accurate FC number to compare to in the morning?