Can I use this calculator for liquid chlorine?
No. Liquid products require their own concentration basis and verified density or label-volume model. This tool reports dry granular product mass only.
Pool Chlorine Calculator
Estimate the mass of one supported granular chlorine product for an entered free-chlorine increase. This is quantity planning, not a treatment prescription. Liquid chlorine, tablets and other products are not interchangeable with this model.
Published by Pool Cost Planner. Updated October 19, 2026.
Use a measured water volume and current reading. The calculator does not choose a chemical target.
Match the product before calculating
This model is limited to ProSide Calcium Hypochlorite Granules 68%, EPA registration 100368-6, in a resealable container. Its label identifies 65% minimum available chlorine separately from 68% calcium hypochlorite. Those percentages describe different things. Confirm the exact package and current instructions; a familiar brand name or the word shock alone is not enough.
How much chlorine to add to a pool is not just a volume question
A theoretical mass estimate cannot decide the appropriate target for your water. Use a fresh free-chlorine measurement and a target checked against the matching label and actual pool conditions. Total chlorine is not a substitute for free chlorine. This tool leaves both readings blank and does not infer a treatment from the pool's appearance. Unexpected readings need verification and qualified advice.
Methodology: available-chlorine mass balance
Kilograms of product = liters x positive entered increase in ppm / (1,000,000 x 0.65). The water approximation treats ppm as mg/L. It assumes the stated available-chlorine fraction and no consumption during the change. Actual strength, sunlight, contaminants and measurement error can change the observed result. The 65% figure is a labeled minimum, not a batch assay. No liquid density or fluid-ounce conversion is inferred.
| Water volume | Entered increase | Theoretical product mass |
|---|---|---|
| 10,000 L | 1.3 ppm | 20 g |
| 10,000 US gal | 2 ppm | About 116 g / 4.11 dry oz |
| Any supported volume | Zero or negative difference | 0 additional product |
What the calculation leaves out
Pool volume must be at least 500 US gallons; target entry is capped at 4 ppm for this limited model. That cap is not a recommended target or a swimming-safety test. The result is not a daily consumption forecast, algae treatment, breakpoint calculation or public-health response. It does not assess calcium buildup, stabilizer effects, pH or product compatibility. It also does not model strength loss in an old or damaged package.
Dry ounces, liquid ounces and purchase quantities
The output is mass: grams, kilograms, pounds and dry ounces. A US fluid ounce measures liquid volume and cannot replace a dry ounce in this calculation. The tool does not round a calculated amount up to a bag, estimate scoops or give application instructions. Single-use bags are excluded because their package constraints need separate treatment. A zero addition when the current reading is higher than target is not a lowering or water-removal instruction.
Keep the estimate with the water record
Record the measured volume, date of the test, product identity and the assumptions used. A calculation can help explain a quantity to a service provider, but cannot confirm what actually happened in the water. Use the shock tool only for its separate, label-specific planning scope. Use the chemicals cost tool for a monthly budget; this mass result does not establish how often a purchase will be needed.
Sources and review scope
Sources checked October 19, 2026. Model-specific instructions are not universal guidance. No independent professional review is claimed.
- EPA: ProSide Granules 68%, registration 100368-6, label pages 1, 3-4. Accepted August 14, 2025; PDF pages 3, 5-6.
- Pyrock Chemical: ProSide Cal Hypo 68% product and registration. Publication date not stated; current package documents available from manufacturer.
- CDC: home pool water treatment and testing. Reviewed May 10, 2024.
Related calculators and guides
- Start with measured water dimensions: Pool Volume Calculator.
- Choose a supported water-planning tool: Pool Chemical Calculator.
- Compare the separate label-range planning scope: Pool Shock Calculator.
- Budget supplies separately from quantities: Pool Chemicals Cost Calculator.
FAQ
Why is the calculation based on 65% rather than 68%?
The supported label distinguishes minimum available chlorine from the calcium hypochlorite ingredient percentage. The mass balance uses the former, not a substituted percentage.
Will the predicted increase exactly match my next test?
No. Consumption, actual product strength and imperfect measurements are excluded. A calculated result is not a verified final water reading.
Can the result tell me when it is safe to swim?
No. Follow the current label and applicable guidance, and obtain qualified advice for abnormal readings. The tool does not make a re-entry decision.