Drop pH to 7.0
Run the pump and aerate as much as you can - fountains, waterfalls, spa jets, or a homemade aerator. Search that term here and you find some good ideas.
Give it a couple hours (or less if you're antsy) and recheck pH and TA. Add whatever acid you need to get pH back down to 7.0.
Repeat.
You won't see a lot of TA drop each time, but pH will keep coming back up. Pool Calculator will tell you the effects of adding chemicals, down near the bottom. You'll see that you may expect 5, 8, maybe 10 ppm drop on TA each time. So you can probably skip the TA testing some times to save reagent. When TA starts getting close, then pay close attention. And stop the vigorous aeration, lest it drop too low.