Here's what's happened so far:

Even though the hot AZ sun was beating down, I put in 6 gallons bleach at 2 hour intervals today, never getting a Cl reading but knowing something was happening because of the pea soup I'd created. Had to leave for a party and when I returned at around dusk, I could see the bottom and there was a peachy blanket of precipitate on the bottom with some floating, too. I backwashed, vacuumed to waste and just added another 2 gallons of bleach. Now that I don't have daylight it's hard to tell how dark the cloud is when I add the Cl but I don't think it's as dramatic as those first applications. My latest readings were Ph 7.6, Cl 0, and TA 240. I'm off to buy more bleach so I can keep at it all night.

I'd welcome any suggestions, kudos, or whatever anyone has to offer to keep me on the right track.

Thanks,
Deborah
above ground 10,000 gal fiberglass sectional with vinyl bottom
100 lb sand filter