Always better to add things gradually rather than a huge dose all at once and overshoot your target. 8 lbs. of Borax at one time is a lot. We'll see what your pH reading is in the morning, but in the future, I would advise against adding so much at once.

It is fine to add bleach and Borax at the same time. I do it all the time with no problem.

Not sure about the "white spray." Did it start before or after the Borax addition?

Repost in the morning with new numbers and tell us how the water looks. The more times per day that you can add enough bleach to get back up to shock level, the better. There is no such thing as testing and dosing with bleach too often. Glad it is looking better.