In The Swim Spa and Hot Tub Alkalinity Increaser 2 lbs.
Use when total alkalinity drops below 80 ppm.  Balanced alkalinity levels (between 80-120ppm) make your pH and chlorine levels easier to control. The product is granular and is chemically known as Sodium Bicarbonate.  Dosage: 1-2 oz. per 500 gallons.