Do you use a solar cover? If not, I'd consider getting one as it will interfere with the out-gassing from aeration that raises pH. Also, point your returns further down so there's little bubbling. BTW, is your pool new? If so, you may well be dealing with curing, which is typical of new hard-sided pools..and the curing raises pH, too.

You gave us current CH and TA numbers, but what were they before you drained the pool down, when you got the scaling? You shouldn't have scaling with your current #s.

I find I frequently can run TA far lower with stable pH--like as low as 60ppm, especially if I've seen pH rise.

Just some ideas...