What CYA level should I run?

Chlorine pools usually aim for 30–50 ppm; saltwater pools run higher, around 70–80 ppm, because the generator makes chlorine continuously. Higher CYA means you must hold a higher free-chlorine level to keep the same sanitizing power.

My CYA is too high — how do I lower it?

There is no chemical that removes cyanuric acid. The practical fix is to drain and replace part of the water with fresh. That is why it is worth adding stabilizer conservatively and retesting rather than overshooting.

Do dichlor and trichlor add CYA on their own?

Yes. Both stabilized chlorines leave cyanuric acid behind every time you use them, so a pool sanitized with tablets can climb into over-stabilized territory over a season. Watch your CYA and switch to liquid or cal-hypo if it gets high.

Stabilizer (CYA) Calculator

Find the cyanuric acid needed to raise your stabilizer (CYA) to target — the sunscreen that keeps chlorine from burning off, sized to your pool volume.

Inputs

Pool volume — gallons

gal

Current CYA

ppm

Target CYA

ppm

Product — ~100% cyanuric acid

Results update as you type — no submit

Stabilizer to add

2.5 lb

≈ 1.14 kg

CYA change20 ppm

ProductCyanuric acid (stabilizer / conditioner)

Formula

raise CYA by 20 ppm in 15,000 gal
stabilizer = 2.5 lb ≈ 1.14 kg

Add chemicals to water, never water to chemicals. Broadcast over the deep end with the pump running, then retest before adding more.

Doses are estimates from published product concentrations — always follow the product label, add chemicals to water (never the reverse), test with a kit, and retest after dosing.

MeasureShedmeasureshed.com/calculator/cya-stabilizer-calculator

Stabilizer (CYA) — dose sheetUNITS: US GAL · ppm

Inputs

Pool volume15,000 gal

Current CYA20 ppm

Target CYA40 ppm

ProductCyanuric acid (stabilizer / conditioner)

Results

stabilizer to add2.5 lb

Other units1.14 kg

CYA change20 CYA ppm

Safe dosing: add product to water (never the reverse) · broadcast with the pump running · wait and retest before re-dosing · keep chemicals apart and dry.

Shopping list

☐ 2.5 lb (1.14 kg) — Cyanuric acid (stabilizer / conditioner)

Formula

raise CYA by 20 ppm in 15,000 gal

stabilizer = 2.5 lb (1.14 kg)

Doses are estimates from published product concentrations — always follow the product label, add chemicals to water (never the reverse), test with a kit, and retest after dosing.SHEET 1 OF 1

How it works

Cyanuric acid (CYA), also sold as stabilizer or conditioner, is sunscreen for your chlorine. Without it, ultraviolet light burns off free chlorine within hours; with it, chlorine lasts far longer. The trade-off is that too much CYA weakens chlorine's punch, so you want it in range, not maxed out. The calculator finds how much to add from your pool volume and the gap to your target.

Stabilizer product is essentially pure cyanuric acid, and CYA is read directly as parts per million of cyanuric acid, so the dose is a clean mass balance: about `13 oz` per `10,000 gal` raises CYA by `10 ppm`. A traditionally chlorinated pool usually targets `30–50 ppm`; saltwater pools often run `70–80 ppm` to protect chlorine from the generator.

Cyanuric acid dissolves slowly — often over days. The gentlest method is to put it in a sock in the skimmer basket or broadcast it into a bucket of water first; do not dump granules on plaster, where they can etch. Run the pump, wait, and retest before adding more. Add product to water, and confirm the reading with a test kit.

Worked example

Volume `15,000 gal` · cyanuric acid `20 → 40 ppm` (`+20 ppm`)
stabilizer = 20 × 15,000 × 3.785 ÷ 1,000 ÷ 1,000 = `1,136 g` = `40 oz` = `2.5 lb`

Questions about cyanuric acid

About 13 oz of cyanuric acid per 10,000 gal. To go from 20 to 40 ppm in a 15,000 gal pool you need roughly 2.5 lb. Because it dissolves slowly, add it and wait a day or two before retesting.

SOURCES — Cyanuric acid label (~100%) · ppm = mg/L (≈13 oz / 10k gal / 10 ppm)

Doses are estimates from published product concentrations — always follow the product label, add chemicals to water (never the reverse), test with a kit, and retest after dosing.