Reference
Pool Water Chemistry Cheat Sheet
The reference a technician actually needs on the truck: target ranges, how often to test each parameter, what to add when it is out of range, and the order to correct things in.
| Parameter | Target range | Test | If low | If high |
|---|---|---|---|---|
| Free chlorine | 1–3 ppm | Every visit | Add liquid chlorine or cal-hypo | Pause the chlorinator and let it dissipate |
| pH | 7.4–7.6 | Every visit | Soda ash, ~6 oz / 10k gal per 0.2 | Muriatic acid, ~10 fl oz / 10k gal per 0.2 |
| Total alkalinity | 80–120 ppm | Weekly | Baking soda, ~1.5 lb / 10k gal per 10 ppm | Measured acid doses over several days |
| Calcium hardness | 200–400 ppm | Monthly | Calcium chloride, ~21 oz / 10k gal per 10 ppm | Partial drain and refill |
| Cyanuric acid | 30–50 ppm (60–80 salt) | Monthly | Stabilizer, ~13 oz / 10k gal per 10 ppm | Drain and refill — cannot be removed chemically |
| Salinity | 2,700–3,400 ppm | Monthly | Pool salt, 8.35 lb / 1k gal per 1,000 ppm | Dilute with fresh water |
| Filter pressure | Clean baseline +8 psi | Every visit | Check for a clogged pump basket or low water | Backwash or clean the cartridges |
How this is calculated
- Correct in this order: total alkalinity, then pH, then calcium hardness, then stabilizer, then sanitizer. Correcting out of order means re-doing work.
- Test free chlorine and pH on every visit, total alkalinity weekly, and calcium hardness, CYA and salinity monthly or after any water replacement.
- Never mix two chemicals together, dry or wet. Add one, circulate, then add the next.
- Log every reading. A single reading tells you what to add today; a trend line tells you what is actually wrong with the pool.
Figures follow commonly published residential pool references and are guidance, not a substitute for testing your own water. Always follow the product label and add one chemical at a time.
Frequently asked
- What are the correct pool chemical levels?
- Free chlorine 1 to 3 ppm, pH 7.4 to 7.6, total alkalinity 80 to 120 ppm, calcium hardness 200 to 400 ppm, cyanuric acid 30 to 50 ppm (60 to 80 ppm on a salt pool), and salinity 2,700 to 3,400 ppm where a salt cell is fitted.
- How often should pool water be tested?
- Chlorine and pH at least twice a week for a home pool and on every visit for a serviced pool. Alkalinity weekly, and hardness, CYA and salt monthly. Test more often during heat waves, heavy use or after storms.
- What order should chemicals be adjusted in?
- Total alkalinity first because it buffers pH, then pH, then calcium hardness, then cyanuric acid, and sanitizer last. Each step changes the readings after it, so working backwards wastes chemicals.
- Why is water balance more than chlorine?
- Chlorine only sanitizes efficiently inside a narrow pH window, and unbalanced water attacks the pool itself. Aggressive water etches plaster and corrodes heaters, while scaling water fouls tile, filters and salt cells.
Next tool
CalculatorChlorine & shock calculatorHow much cal-hypo, dichlor, trichlor or liquid chlorine to add — including breakpoint shock.Open CalculatorpH & alkalinity calculatorAcid, soda ash and baking soda doses to bring pH and alkalinity back into range.Open CalculatorSalt & stabilizer calculatorPounds of salt for your target salinity, stabilizer doses, and the drain math for high CYA.Open
Related reading
ArticlePool Updates Homeowners Appreciate After Every VisitLearn which pool updates homeowners value after every visit, from chemistry logs to photos, equipment notes and payment links.Read ArticleHow to Hire for a Growing Pool Care BusinessLearn how to hire for a growing pool care business, from first technician roles to interviews, training, retention and scalable systems.Read ArticlePool Technician Tools That Improve Service QualityExplore pool technician tools that improve water testing, checklists, routing, photos, repairs, and homeowner trust for better service quality.Read