Quote Originally Posted by ubalr1
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.
Ubalr, welcome ot the forum! Your numbers are certainly from a pool store, honest folks who do their own testing get numbers that end with "0". Your cya and hardness results make a partial draining a good idea, but only if the fill water is lower in calcium. My best advice is to get a good test kit and learn how to use it, take control of your pool. Your pH is way low, dump a box of Borax in ASAP, and a couple gallons of regular (unscented) bleach in the pool -NOW (with your cya so high, you need a lot of chlorine) I'm sure that others who know more about the chemistry side will post, but do what I'v said as soon as you can. Good luck with the pool, you can escape the Biocrud cycle if you take matters into your own hands.