Caveat:

Watermom is, of course, correct that Borax will not mess with your T/A.

HOWEVER, you must understand that pH and T/A are linked and when pH goes up, T/A goes up, and when pH goes down, T/A goes down. The ONLY way to raise pH without raising T/A is by aeration--fountains, splashing kids, etc.

So, in this vein, if you use soda ash (Washing Soda) your pH will go up but so will your T/A. If you were to lower you pH to back where you started, your T/A would be higher than when you started.