I have not been able to hold the water at FC 25ppm for overnight. That's where I'm at. I have met 2 of the 3 criteria that Watermom told me to achieve. Hold FC at shock level of 25ppm, CC less than 1 (which I have achieved!) and the water is clear (which is beautifully clear). The FC seems to go down over night by 1-2 ppm. I add more bleach to bring it up and I think I'm ok, then test again in the morning and down it goes. It has been a little frustrating. We have been vacuuming to waste and adding water when needed. Not sure what else to do...