Before I pose my question here are my pool stats

16x34 IG pool with SWG

latest results

FC 4.92
TC 4.97
CC 0.0
pH 7.80
hardness 170ppm
Alk 210 ppm
CYA 15 ppm
Salt 2900 ppm

They suggested I use a product called AQUA pH minus to bring down the Alkalinity to between 100 and 120 ppm which is fine. I just wondered if there was a cheaper product that I could use to control the pH and Alk. I am a newbie but still trying to save on costs. I just bought 8kg which is about 17lbs of this stuff for $30 canadian, is that a good price, is there something cheaper? Can i use muratic acid is it cheaper per treatment?

Since I have a SWG I know the tendency is for it to drive the pH up, so I am sure we have to stock up on the appropriate chemicals.

Thanks