Pool Chemical Log
Free pool chemistry calculators for salt, shock, pH, alkalinity and stabilizer, and a chemistry log that stays in your browser, each tied to its source.
- ppmFree chlorine 1.2 ppm: Low. Range at least 2 ppm, CDC, for home pools.
- ppmCombined chlorine: Not tested. Range 0.4 ppm or less, MAHC 2024, a public-pool code.
- pH 7.6: In range. Range 7.0–7.8, CDC, for home pools.
- ppmTotal alkalinity 90 ppm: In range. Range 60–180 ppm, MAHC 2024, a public-pool code.
- ppmCalcium hardness 250 ppm: In range. Range 200–400 ppm, MAHC 2024 Annex, guidance for public pools.
- ppmCyanuric acid 50 ppm: In range. Range 90 ppm or less, MAHC 2024, a public-pool code.
- ppmSalt 3,200 ppm: In range. Range 2,700–3,400 ppm, Hayward AquaRite manual.
Not a colour chart: read your strip against its own bottle.
Safety: Never mix:
Chlorine products with acid; this could create toxic gases.
(CDC, Use Pool Chemicals Safely). Which chemicals never to mix
Tools
Measure
Dose
Pool Chemical Calculator: Doses in the Right OrderEnter your pool's readings and targets for a dosing list covering chlorine, alkalinity, stabilizer and calcium, in a health department's order of addition.
Pool pH and Alkalinity CalculatorWork out how much muriatic acid, dry acid, baking soda or soda ash moves total alkalinity to target, and your carbonate alkalinity after the CYA correction.
Cyanuric Acid Calculator: Pool Stabilizer to Add or DrainWork out how much cyanuric acid (stabilizer) to add, or how much water to drain and refill to lower it, with the free chlorine your CYA level calls for.
Pool Shock Calculator: How Much Chlorine to Shock a PoolWork out how much liquid chlorine, cal hypo, dichlor or trichlor raises free chlorine to a shock level, with breakpoint for combined chlorine.
Pool Salt Calculator: Pounds and Bags for Your Salt SystemWork out how many pounds and bags of salt to add for a Hayward, Pentair, Jandy or CircuPool salt chlorine generator, from your pool volume and salt reading.
Check balance
Keep a record
How the numbers are checked
Pool chemistry calculators for a home pool, and a chemistry log that stays in your browser. Doses here are computed from published constants — NIST's unit factors and PubChem's molar masses — rather than read off a rounded rule of thumb, and each one is cross-checked against a published dosing table. Every range a reading is held up against is printed with the body that set it and the words it rests on.
How the calculators are checked sets out the documents behind them, the constants, the rounding and the tests each one has to pass.
Seven guides go deeper than any one calculator: the order for lowering pH or raising alkalinity, which chemicals never to combine, what cyanuric acid is actually doing in the water, a green pool's first steps, the order for opening and closing a pool each season, and how to read an EPA-registered chemical label.
Guides
Fixing a problem
A Green Pool: What to Do FirstThe order for bringing a green or cloudy pool back — test, brush, shock, filter continuously, retest — before reaching for an algaecide.
How to Lower pH in a Pool: the Order, Not a DoseThe sequence for lowering pool pH safely — alkalinity first, small doses of acid, retest — and why this site prints no acid dose for a pH move.
How to Raise Alkalinity in a PoolThe order for raising total alkalinity with baking soda or soda ash, why it comes before pH, and where the pH and alkalinity calculator picks up the dose.
Knowing your chemicals
Never Mix These Pool ChemicalsWhy pool chemicals that look like ordinary powders and liquids can react violently together, with real incidents from EPA's own safety alert.
Reading a Pool Chemical LabelHow to find the active-ingredient percentage, the signal word and the re-entry limit on an EPA-registered pool chemical label, using this site's saved labels.
What Cyanuric Acid Does in a PoolHow cyanuric acid stabilizes chlorine against sunlight, why it isn't free, and what the 45:1 ratio and the 90 ppm ceiling are protecting against.
Seasons
Season opening reminder
One email in spring when it's time to open the pool, with the opening order from our checklist guide.