Hallelujah! After 5 days and 23 gallons of 10% Cl, I've reached the other side of the river Styx . Chlorine held at 20-25 for >8 hours even during the day, so I put some polyquat 60 in to help prevent regrowth and maybe clear the water just a little more. The water was pretty clear, but still just a little dull. Plan to put solar blanket on tomorrow morning and maybe will be swimming for the holiday. Yippeee! Thank you for your help.