I'm usually good at this stuff......

[duraleigh]

Yes, muriatic will move Alk down along with pH.

THIS IS A TEMPORARY IDEA....NOT A LONG-TERM SOLUTION
If you wanted to get really clever you could shut off your SWG and put about 4 trichlor pucks into the skimmer....take them out anytime you shut off the pump.

The pucks will provide chlorination for your pool AND drive down the pH. Unfortunately, they also add CYA to your pool so I wouldn't use them if the CYA got to 50.

Your SWG and the acid are fighting each other pH-wise. Pucks are on the same team as the acid.

Your choice as to what to do but that SWG at full bore is problematic.