You can use Muratic Acid to lower the alk in the mixing container. It will need to be stirred for a few days for the PH to come back up. It is safe and easy. If you otherwise like a salt, then high Alk is no reason to change. I have done this to my IO for nearly every water change for probably 15 years.
Gallons * desired dKh drop *.123 is the MLs of Muratic Acid to use.