Question: how much hth shock treatment to use?
Answer: If the water looks good and you just want to boost the chlorine level a bit, add ½ bag per 10,000 gallons. If the water is hazy or cloudy use a full bag per 10K gallons, and if there is algae use 2-6 lbs per 10,000 gals, depending on the extent of the algae bloom.