I didn't know you had an SWG since that was not in your signature. SWG pools tend to rise more in pH in part due to the increased aeration from the hydrogen gas bubbles. Also, if you have a short pipe run between your SWG and the closest return, there may be undissolved chlorine gas outgassing. If you point that return more downwards, that might help. Finally, you can consider adding 50 ppm Borates to your pool. Though that may not lower the amount of acid you need to add, it should reduce the rate of pH rise and will help reduce scaling in your SWG cell.