It's working exactly as it is supposed to. Acid lowers both pH and TA while aeration forces carbon dioxide to outgas which causes the pH to rise with no change in TA. A TA of 130 ppm will still cause the pH to rise. In fact, if you were to use a hypochlorite source of chlorine, your TA would need to be very low to prevent the pH from rising. If you plan to use Dichlor-only, then a TA of around 80 ppm is probably about right. It depends on how you will be using your spa -- whether you run aeration jets.