alkalinity at 320!?!?!?

[Bleach=Chlorine?]

Chlorine is more effective at lower band of the recommended pH level so 7.0 would be fine.

[Rangeball]

Sounds like you did the "slug" method, which apparently only works if you get lucky and duplicate conditions recommended in the following thread, which you need to read if you haven't already-

http://www.poolforum.com/pf2/showthread.php?t=191