It sounds like you either are still fighting something or miscalculated. I can't figure powder amounts--but bleach and LC I can do in my head...

Had you measured the pool an hour after you added the chlorine, you would know what the FC was then and there. If it was 4.5, then by this morning, you lost nothing.

Meanwhile, I don't know where you are but this season, for unexplained reasons, EVERYONE around the country seems to be using excessive amounts of chlorine--myself included. I've had to add a gallon of 12.5% the last two days.