A little more info:
Evening of July 7 -added 2 gal bleach
Morning July 8 -tested with the HTH drop tests
Total chlorine 3-6
pH 7.5
Total alkalinity 350
Total hardness 360

Evening July 8
total chlorine 0
ph 7.8

Well water:
Total chlorine 0
pH 7.8 (at least)
Total alkalinity 430
Total hardness 360
Cyanuric acid- not tested

Anything else I should do? Thanks