Re: PH Issues
Just add acid to bring the pH down and everytime you do that the TA will get lowered some as well. In fact, if you were truly adding one gallon of full-strength Muriatic Acid (31.45% Hydrochloric Acid), then this would have the pH drop from 8.2 down to 7.3 and the TA would drop from 120 ppm down to 90 ppm. After that, the pH would then rise. So your TA should be dropping by around 30 ppm per week if you were adding a gallon of acid every week. That implies that you have been adding baking soda or Alkalinity Up to raise the TA -- is that correct?
I would suggest you get the TA down to 80 and not add anything to raise it unless you still find you need to add a lot of acid to lower the pH. With 50 ppm Borates, it's very surprising to find such a large pH rise still occurring so quickly, especially after turning off all the waterfalls.
If you don't have a lot of sunlight and if your SWG is already set fairly low, you could see what happens if you turn off the SWG for one day. If you find the pH rise to still occur, then it's the higher TA plus other aeration sources or some other mystery. If you find the pH rise to significantly slow down, then the SWG is the main culprit, possibly from outgassing chlorine gas in which case I would ask whether the SWG is very close to the pool itself (i.e. short return lines) and whether the returns are pointed up, straight or down.
The CH could rise if you've got a lot of evaporation and your fill water is high in CH. You can test your fill water to see. Perhaps the TA in the fill water is also high and helping to keep the TA from dropping quite as much, though it would take a heck of a lot of evaporation for this effect to be very noticeable in a short time.
Richard