Water looks great - probably the best ever. I dropped in 4.5 gals of ultra last night and the cl went from 7.5 to 18. According to the calculator on here, it should have taken it up to 25PPM, which was my target. Either Wal-Mart has some weak Ultra Bleach, or my pool is larger than I think. Any suggestions?

Last night.
FC = 18
This morning
FC 13.5

Picture from this morning.

Pool.jpg