Thursday night I added 2 gallons of bleach and 1 box of borax; PH was not quite 7.0 but more likely 6.9.
Then I added 4 more cups of borax.

Friday 11am, PH=7.2, FC=10.5.
Then I added 3 cups of borax and went to work.
Water is looking better now but seeing some black/gray dirt on the bottom -- another round of vac should remove them.

Friday night plan, please advise.