The pool already had a high chlorine reading of 10.
I turned off the feeder to drop the chlorine.
Next day someone turned off the moter so the pool became green.
Next day I shocked it . I also drained half of 40000 gallons and refill it. At this point I still left the feeder off until the next day when the pool filled up. Even though they were no tabs in the feeder. I still had a reading of 10.