Between being out of bleach, laziness, busy schedules, and cooler weather, I neglected to add bleach like I should have. Honestly, I think I went about 4-5 days without adding any. Before that, I kept my FC levels between 5-9, with a CYA of 65-70. Every morining I expected my pool to be green, but it stayed clear. Last night I decide to finally get back on track with the bleach, so I tested it, fully expecting a FC reading of 0. To my surprise, I read a FC of 4?! I know my CYA level is a little high, but I was not expecting my FC to hold for that long. Anyway, just thought I would share!