My 15,000 gal gunite pool is 1 week old and the total alkalinity is still too high. It started at about 320, now it's at 210. Should I be in panic mode? Will my plaster start getting rough?

Is this normal for a new pool? I brushed 1-2 times per day for a week, and have an in-line chlorinator with tri-chlor tablets.

Here's the other numbers (I only have the Pentair 5-in-1 test):

chlorine: somewhere between 1.5 and 3.0
pH: 7.6
TA: 210

My manual from the test kit says to add acid to lower the TA, but won't that also lower my pH? How do I lower the total alkalinity without lowering the pH?