you wont loose fish.
This is were your acros (if u had some) would be stressed.
normally u would just let the extra alk be consumed over a day or 2, it's not a extreme jump for what u have in the tank.
You want to relax a little, not try so hard to fix these numbers every day.
Talked with the boss today and he brought up a good point about your new mix at 6.8,
maybe you had some sort of precipitation when you mixed, u should check into that one also.
Keep chugging along, it will all come together for you and be that much easier for you.
Edit: sorry, just assumed 8.5 was alk reading, ph different story.
a quarter of a shot glass raised it that much?
what is your normal ph at?