Pool Alkalinity Calculator — Label Dose & Retest
Estimate sodium bicarbonate from measured pool alkalinity and your product label. Plan packages and recalculate from a fresh water test.
Test → plan → circulate → retest
Raise total alkalinity with a clear plan
Use your latest water test and a target chosen for your pool. Match the amount to your sodium bicarbonate product label.
Water and latest test
Copy the dosing rule from your label
Use a sodium bicarbonate alkalinity increaser. Enter the mass, water volume and alkalinity increase in the same instruction.
Stock and package planning
Estimated total to reach your target
5.6 lb
2.54 kg of sodium bicarbonate
PHTA reference estimate, not your product’s exact instruction.
This is the estimated total, not a single-addition instruction. Follow the product label, circulate as directed and retest TA and pH before adding more.
See the calculation
1.4 lb × (10,000 / 10,000 US gal) × (40 / 10 ppm) = 5.6 lb.
Alkalinity is buffering capacity, expressed as calcium-carbonate equivalent. It is different from pH. Rounded dosing rates and actual water tests are uncertain; no predicted pH or swimming-safety decision is made here.
Record an addition and a fresh test
After circulation following your product instructions, enter a new measured TA. This replaces the previous reading. The addition is a record, not a second deduction from the new dose.
Records stay in this open page only. Reloading clears them. If purchase planning is enabled, a recorded addition also reduces available stock.
Try a worked example
Examples illustrate two dosing bases. They do not select a suitable target for your pool.
Choosing a target and understanding this estimate
Your sanitizer, equipment, product instructions and local requirements affect the target. PHTA’s published guidance distinguishes 80–100 ppm for some hypochlorite sanitizers and 100–120 ppm for some acidic sanitizers; these are context, not an automatic recommendation. A test’s total alkalinity can include cyanurate alkalinity. This tool uses measured total alkalinity; it does not calculate corrected carbonate alkalinity or saturation balance.
If TA is already above target, do not add a raising product. Check TA and pH together and follow a suitable reduction procedure from your product or equipment provider. This tool does not size an acid addition.
The reference uses the rounded US sodium bicarbonate row from PHTA 2021 Appendix B, adjustment guide and label worksheets. Its separately rounded metric row is not silently substituted on unit changes. Leslie’s product instructions provide the illustrative 1.5 lb rate. Always check the actual label you have.
