If you drained & refilled ( partially) & shot the water through all the jets, then drained the remenants, that should have done it ( gotten rid of the bacq).
The only thing I would have done differently is used a Tub Clean product first ( thats the stuff that you filter through before draining),
but by changing your filter, I would have thought that you did enough.

I use BBB, but I use bromine not bleach, so i guess I can't help you there.
Chlorine does burn-off faster at high temperatures ( than bromine).

Do you have some sort of stabalizer in the tub?
if you do, then keep adding chlorine slowly until you can maintain levels.

I think with chlorine, you want to shoot for around 7+ ppm
( but ask waterbear )