I have repeatedly measured my TA at 80 ppm with the TFT test kit. It has been more or less the same for more than 5 years. However, I have to input 200 ppm in Pool Math to get the amount of HCl required to achieve the desired pH change. It takes about 64 oz. of 31.45% HCl to drop the pH from 8.2 to 7.5. It only takes two or three days for the pH to return to ~8. I have never added borates. I considered that maybe aeration was raising the pH, but shouldn't that lower TA?