Bringing down the TA is a long drawn out process. (See the Sticky in Alkalinity and Calcium Hardness by Pool Doc)

I would continue adding chlorine to help the SWCG as much as possible, and carry on aerating with the pH down to 7.0 - 7.2. the pH will continue to creep upwards, because of your plaster pool and the TA, so it's PITA you have to endure until your pool chemistry settles down.

Poconos, it should be possible to check the DC amps on the DG-220 Controller, and if it is low, (<4 amps) I would check the cell for any scale build-up, and clean with 20% Muriatic acid.

Let us know how you make out.

Pat