Been following this site for a week and it's a lot too late for me. I have beeen using pucks for years. While awaiting for the arrival of my kit, I had my water tested at a local pool store. Here are the results:

IG Vinyle 20,500
Temp 83
PH 6.98
FC 21.31
TC 22.9
CYA 212

They didn't test for ALK saying CL was too high to get an accurate reading.
Looking forward to your advice. Great site.