Ok, I'm a Newb here! So please go easy on me! My Pool guy just retired & I am attempting to do my pool myself. Went to ACE Hardware to get Water Tested. Test recommended putting 20 LBS. of Sodium Bicarbonate in. I went to Dollar Store & bought 20 LBS. of Arm & Hammer Baking Soda, put it in pool. Ran Pump for one day. Went back to ACE & got retested & it now still says I need 17 Pounds of Sodium Bicarbonate. Asked ACE Salesperson why & he said the Arm & Hammer product is not pure & concentrated enough & he pointed to a 20 LB. Bag he sold for $23. & told me this is what you have to use. Am I wrong? Or is this exactly the same product? My PH is 8, It also advised I add 6 LBs. Muriatic Acid. Thanks in advance. I know for a fact my old Pool guy was slacking off on the Chemicals due to me having a 20' X 40' Pool & him wanting to save money & just get away with doing the bare minimum.