high pool alkalinity after refilling with mains

[hin83]

after refilling the pool with mains water . after refurbishment of pool suface. i have a high total alkalinity of 250+ but my ph is good at 7.4.
the pool is 20,000 gals. how do i reduce this to a lower acceptable level.

[chem geek]

You follow the procedure outlined in this post. It's going to take a LOT of acid -- both to get the pH low and especially to add during the aeration pH rise cycling.