Purchased house with my first ever pool. SWG 30,000 gallons. CYA reading at 7ppm from one store, 5 at another, and 0 on a test strip. Poolmath says to add 18lbs, TFP says to do it through a sock at the returns. Do I just add another (3) socks full everyday for a week to get it up assuming each one takes a day to dissipate? First pool and have read horror stories of too much CYA also both pool stores said ‘oh you have a SWG you can have under 10 CYA it’s fine’ but I don’t trust them.