It's generally a bad idea to add both soda ash AND baking soda. Usually, if you want to raise pH and TA you either add Borax and baking soda, or just soda ash, because the latter increases TA levels for any pH level.

BTW, Arm&Hammer Washing Soda in the yellow box in the detergent section of your supermarket is soda ash--exactly the same stuff the pool stores sell.

You may find with such a high TA you have trouble keeping your pH down, and you'll have to lower it just by lowering your pH.