This Natural Chemistry spa chlorine concentrate provides active chlorine residual to sanitize spa water, creating a clean, safe spa environment. It is part of the Sanitize group of products used in the Spa Ease program. Controls bacteria in spa water. Easy to dose and measure cap. Recommended dosage are 1/2 teaspoon per 100-gallons of water to maintain and 1-teaspoon per 100-gallons of water for super chlorination. It can be apply with pump on and adding maintenance dose as an initial treatment. Then it repeats at 15 to 20 minute intervals until a residual of 3-5 ppm of available chlorine is established as determined by a test kit. Super chlorination may be needed on a nightly basis in a heavily used spa or as infrequently as once a week in a moderately used spa. Includes 12 chlorine concentrate container per pack. Available in 2-pounds container.