midtngal said:
If I want to raise that to the 50 ppm mentioned here and I add the 600 oz that doing so calls for, the pool calculator tells me that this would raise my pH by 6.12 and my TA by 109. So should I then add the acid to bring that back into range??
If you are adding borates using borax you need to add the correct amount of muriatic acid at the same time to keep the PH steady. Adding acid will not affect the borates in the water. It is
very important that you rebalance the PH after adding borates. Even with borax and acid being added at the same time the balance may not come out exactly right and you need to check the PH and make any final adjustments as needed after everything has mixed for a few hours.
The borates level is like the CYA level, it will normally only go down because of water replacement (splash out, backwashing, rain overflow) so it only needs to be checked at the start of the season and any time you suspect significant water replacement has occurred.
Adding borax and acid will have a small effect on TA, but the borates PH buffer and the TA PH buffer are essentially independent of each other. It is still possible to change the TA after adding borates, it is just significantly more difficult.