OK, so yesterday afternoon I added 8lb Borax, 8.4 gal (6x1.4Gal bottles) 6% Bleach, and 4lb baking soda. I didn't get a chance to test again until this morning, when I had 3ppm Free Chlorine, pH still below 7.0, and 40ppm Total Alkalinity. An hour ago I added another 6 gal 6% bleach, 8lb Borax and 4lb Baking Soda, and will test again in another hour.

Meanwhile I've managed to pick up some 12.5% Sodium Hypochlorite - is it reasonable to assume that 4gal 12.5% is roughly equivalent to 8.4gal 6%, so I should halve the volume to add the same dose?

I'll be testing and dosing every couple of hours today, tomorrow, and probably Monday, hoping for some decent progress!

How can I tell if the algae is dying at 10, 15, 20ppm? Will the water clear, or will dead algae just turn it a different color until it's filtered out?

Thanks!
Mark