Methodology
The formulas and assumptions behind every calculator.
This page keeps the calculator methods in one place. It is meant for auditing, not for replacing product labels, equipment manuals, local rules, or professional advice when pool water is unsafe or unstable.
Assumptions
- The ppm increase is target salt ppm minus current salt ppm. If current ppm is higher than target, the calculator switches to dilution guidance.
- Bag count rounds up for shopping because pool salt is usually sold by the full bag.
- A generic target such as 3200 ppm should be replaced by the target range in the saltwater chlorine generator manual.
Assumptions
- For liquid products, product pounds are converted to approximate gallons using 8.34 pounds per gallon.
- The calculator handles immediate chlorine additions. Slow-dissolving tablets are not a fast ppm correction.
- If current free chlorine is already above target, the dose is zero and retesting is the next step.
Assumptions
- pH adjustment is not perfectly linear. Total alkalinity, borates, temperature, aeration, and test accuracy can change the real dose.
- This page intentionally supports only two products with clear planning factors: 31.45% muriatic acid and soda ash.
- The calculator caps the first dose so large changes are handled in stages and checked by retesting.
Assumptions
- The baking soda estimate uses a common planning rule of 1.5 lb per 10,000 gallons for each 10 ppm TA increase.
- Lowering total alkalinity is not a one-step chemical add. Acid lowers pH and TA, then aeration helps pH recover.
- The acid result is a staged planning amount, not a one-pour dose. Large alkalinity moves should be split with pH and TA retesting.
Assumptions
- The dose assumes dry cyanuric acid. Liquid conditioner products vary by concentration and should follow the product label.
- If current CYA is above target, the calculator switches to dilution guidance instead of recommending more stabilizer.
- CYA can dissolve and show on tests slowly, so large corrections should be staged and retested.
Assumptions
- Average depth is used for sloped pools because most pool chemical labels dose from estimated total water volume.
- Round and oval pools use geometric surface-area formulas, so steps, ledges, spas, and freeform areas should be estimated separately when they are large.
- The 8-hour turnover estimate divides gallons by 480 minutes and does not replace pump curve or plumbing calculations.
Assumptions
- Liquid chlorine is converted from pounds to approximate gallons using 8.34 pounds per gallon as a planning shortcut.
- The CYA-based target is a planning aid, not a replacement for product labels, local code, or a pool professional diagnosis.
- Old liquid chlorine may be weaker than its label strength, so dose conservatively and retest.