Pool Water Chemistry Calculator 2.0
Enter your pool size and chemistry readings to calculate dosing guidance for pH, chlorine, alkalinity, calcium hardness, cyanuric acid, salt, shock treatment, tabs vs liquid chlorine, and a print-ready service sheet.
Recommended Target Ranges
Pool & Chemistry Inputs
Quick Guidance
Suggested Order
- Fix alkalinity first if it is way off.
- Then correct pH.
- Then raise sanitizer.
- Then fine-tune CYA, calcium, and salt.
- Circulate and retest before adding more.
Chemistry Results
pH Adjustment
Free Chlorine
Total Alkalinity
Calcium Hardness
Cyanuric Acid (Stabilizer)
Salt
Shock Calculator
Tabs vs Liquid Chlorine
LSI / Water Balance Estimate
Overall Summary
Service Call Sheet Builder
Service Sheet Preview
Pool Chemistry Service Sheet
Field chemistry results and treatment recommendations
Pool Chemistry Calculator Instruction Sheet
Use this guide to understand every input, abbreviation, target value, and chemical recommendation used in the pool chemistry calculator. Designed to help pool techs enter accurate data and interpret results quickly in the field.
Recommended Target Ranges
Calcium hardness targets vary by pool surface. Vinyl and fiberglass pools generally use the lower range. Plaster and concrete pools generally use the higher range.
Important Abbreviations
Measure of how acidic or basic the pool water is.
Free Chlorine. The active sanitizer available to disinfect the water.
Total Alkalinity. The water’s buffering capacity against fast pH changes.
Calcium Hardness. The amount of dissolved calcium in the water.
Cyanuric Acid, also called stabilizer or conditioner. Helps protect chlorine from sunlight.
Langelier Saturation Index. A field estimate used to judge whether water is balanced, corrosive, or scale-forming.
Parts per million. Standard concentration unit used for most pool chemistry readings.
How to Use the Calculator
Enter the pool gallons. Almost every chemical recommendation depends on correct water volume.
Choose the correct pool surface because that affects calcium hardness targets.
Enter the current test results exactly as measured for pH, FC, TA, CH, CYA, and salt if applicable.
Use the recommended targets or enter your own target values if your service approach is different.
Calculate chemistry, add chemicals carefully, circulate the water, and retest before adding more.
Input Field Explanations
What Each Chemistry Item Means
Controls swimmer comfort, sanitizer efficiency, corrosion tendency, and scaling tendency. High pH can reduce chlorine efficiency. Low pH can make water aggressive.
The active sanitizer in the water. Low FC can allow algae and unsafe conditions. FC should be maintained in the proper range for normal operation.
Acts like a pH buffer. Low TA can let pH swing too fast. High TA can push pH upward and encourage scaling.
Important for balance and surface protection, especially in plaster pools. Too low can be aggressive. Too high can cause scale.
Protects chlorine from sunlight. Too little means chlorine burns off quickly. Too much can weaken chlorine performance.
Needed for salt chlorine generator pools. If it is too low or too high, the salt system may not operate correctly.
Chemicals Referenced by the Calculator
Used to raise pH.
Used to lower pH and can also be used in alkalinity reduction procedures.
Used to raise total alkalinity.
Used to raise calcium hardness.
Used to raise cyanuric acid.
Used to raise salt concentration in salt pools.
Used to raise free chlorine and for shock dosing.
Convenient chlorine source, but they usually add stabilizer over time, so use with care if CYA is already high.
How to Interpret Result Sections
LSI Meanings
Water is in a generally acceptable balance range and is less likely to scale or corrode.
Water may be too aggressive and may pull minerals from plaster, grout, or other surfaces.
Water may deposit calcium scale on surfaces, heaters, salt cells, and other equipment.
The LSI shown in the calculator is a field estimate and should be treated as guidance, not lab-grade analysis.
Best Practices for Pool Techs
Always trust a good test result first. The calculator is only as accurate as the numbers entered.
Correct chemistry in a smart order. A good working order is usually TA, then pH, then sanitizer, then CYA, CH, and salt.
Do not overcorrect. Large chemical additions are often better added in stages.
Circulate and retest after treatment before deciding whether more chemical is needed.
If CH, CYA, or salt are too high, the proper answer is often partial drain and refill rather than adding another product.
Tabs are convenient, but they can keep increasing CYA. Watch stabilizer levels closely when relying on tabs.
Simple Field Example
A pool tech tests a 20,000-gallon pool and gets these readings:
That tells the tech the pool likely needs:
The calculator then gives estimated starting doses, but the tech should still circulate and retest before additional treatment.