1 · Your pool
Every dose is sized to the gallons here.
Not sure? Open the shape calculator below. Without the size you still see what to add — the amounts wait for it.
2 · Your readings
Nothing entered yet.
Slide each strip to the colour on your test, or tap Type it for the exact number. Anything you leave alone is not tested — it is never guessed, and it changes nothing below.
Starts at 82 — change it if you know yours. It is used for the water balance.
3 · What your water needs
One verdict that counts every warning, then the doses in the order to add them. How this calculator works
Enter your readings to see what your water needs.
Slide each strip to match your test, or tap its number to type it. A reading you leave alone is treated as not tested — never guessed.
Never mix chemicals with each other — each one goes into the pool water on its own, acid into water, never water into acid. Follow every product label and SDS. Doses are sized for the volume you entered; when in doubt, add a little less and retest.
How this calculator works
It runs the same dosing plan our store counter prints for the same water. These are the ranges it holds a pool to, the rules it follows, and the rates behind every dose.
| Reading | Range | Aims for, when out of range |
|---|---|---|
| Free chlorine | 1–3 ppm | 3 ppm |
| pH | 7.2–7.6 | 7.5 |
| Total alkalinity | 80–120 ppm | 100 ppm |
| Calcium hardness | 200–400 ppm | 300 ppm |
| Cyanuric acid (stabilizer) | 30–50 ppm | 40 ppm |
| Salt (salt pools) | 2,700–3,400 ppm | 3,200 ppm |
- A reading inside its range is left alone — a balanced pool is never sold chemicals. A reading outside it is aimed at the middle of the range.
- The water balance is the calcite saturation index (LSI), computed from temperature, pH, alkalinity, calcium, stabilizer and dissolved salts with published thermodynamic constants — the same model the Orenda calculator uses. Balanced is within ±0.3. When the water would still be out of balance, pH, then alkalinity, then calcium are moved INSIDE their ranges until it lands.
- Free chlorine is raised when it is under 2 ppm, to 3; above 5 ppm it is high. Above the 30–50 ppm stabilizer range the calculator also says what the published FC/CYA guide asks — free chlorine of at least 7.5% of the CYA — because high stabilizer slows chlorine; it does not "lock" it.
- Acid is ONE addition, sized by the alkalinity it removes, and never takes a pool below pH 7.2; the rest is aeration. Alkalinity is raised before pH, and soda ash is sized only for the gap the bicarbonate leaves.
- Stabilizer, calcium and salt come down only by replacing water. The notes say how much, and it depends on the numbers — and, for calcium, on your fill water.
- Salt pools: the cell makes chlorine from the salt. A low chlorine reading means turning the cell up as well as catching up with a dose; salt-cell makers print their own ranges, so check your cell's manual (Hayward's Aqua Rite manual, for one, gives 2,700–3,400 ppm salt with 3,200 optimal).
- Every dose line says what it assumes — the product's strength and the rate it was sized at. Add chemicals one at a time, in the order shown, with the pump running, and follow the label.
- This is the same plan our store counter and our technicians print for the same water.
Got your plan? Here is what comes next
The calculator is the first thing our store counter does. This is the rest of it.
Get what your plan calls for
Every product a step names is in our shop — the same ones on our store shelf, shipped nationwide.
Shop pool chemicals →Check your readings, free
A strip is a rough read. Bring a water sample to the store for a free digital test — about five minutes — and get the same plan from exact numbers.
Free water testing →Rather not do this every week?
We test the water, balance it and add the chemicals for you. Weekly pool service in Dallas–Fort Worth, from $165/month.
See service plans →Water still not right?
Cloudy, green, or chlorine that will not hold — tell us what you are seeing and get the fix, step by step.
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