Lastest water test at local pool store:
CYA 168
TC 0.6
FC 0.6
pH 6.9
TA 126
TH 527
TDS 2100
20,000 gal, in-ground gunite
Cartridge filter

We are having to shock every week. We are currently stuck in that "Bioguard is the best" trap. We use the Smart Sticks in our skimmer and the Bioguard shock products.