How much chlorine to add to a pool? Dose table per m³
For normal maintenance of a family pool, the chlorine dose is 200–250 g per 25 m³ per week in tablets (slow trichlor), or 5–10 g/m³ in granular chlorine. For shock treatment (after rain, green water, or a heavily used pool) the dose is 15–20 g per m³ of shock chlorine. The target is always free chlorine between 1 and 3 ppm, measured with a test.
Paso a paso
- 1
Work out your pool’s volume in m³
Length × width × average depth (in metres). A family pool of 8 × 4 × 1.5 m holds 48 m³. If it’s oval or round, use π × radius² × depth.
- 2
Weekly maintenance with tablets
200–250 g of slow-chlorine tablets (200 g trichlor) per 25 m³ in the dispenser or skimmer. A 50 m³ pool → 2 large tablets (400 g) per week.
- 3
Measure free chlorine with a test
Every 2–3 days with a test strip or colorimetric test. Target: 1–3 ppm of free chlorine. If it’s low, add more; if it’s very high (>5 ppm) reduce the dose or air the water for a day.
- 4
Shock treatment
After heavy rain, if chlorine drops to 0, or if the water starts to turn green: 15–20 g/m³ of granular shock chlorine dissolved in a bucket and poured around the pool at dusk.
- 5
Adjust the pH first
Chlorine only works well at pH 7.2–7.6. If the pH is high, no chlorine will disinfect properly even if you add double. Measure the pH and adjust before measuring chlorine.
Productos recomendados
Los mismos que te llevarías de nuestra tienda física en La Cañada (Paterna).
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How much chlorine for a 30 m³ pool?▾
For maintenance: 240–300 g of slow-chlorine tablets per week (1 large 200 g tablet + 1 small). For shock treatment: 450–600 g of shock chlorine (15–20 g/m³ × 30 m³).
How often should I add chlorine?▾
Slow-chlorine tablets: every 5–7 days in the dispenser. Granular/shock chlorine: only when free chlorine drops below 1 ppm (measurable with a test) or as a one-off treatment.
Can I mix chlorine tablets with shock chlorine?▾
Yes, they’re compatible if you add them hours/days apart. NEVER mix them directly (in the same bucket or the same dispenser) — the reaction is violent and dangerous.
Why does chlorine evaporate so quickly?▾
Sun + high temperature break chlorine down. If you apply it during the day in strong sun, 30–50% is lost within hours. That’s why treating at dusk and using a stabiliser (cyanuric acid) is recommended for outdoor pools.
Sigue leyendo
Green pool water? How to clear it up in 24–48 hours
Green water = algae. Shock chlorine + algaecide + flocculant, in the right order. Results in 24–48 h.
Types of pool chlorine: tablets, granular and shock compared
Tablets (maintenance) · Granular (quick adjustment) · Shock (emergency). Three uses, three products.
How to lower pool pH: dose and product
pH > 7.6 = irritation + useless chlorine. Liquid or granular pH reducer, dose 1–1.5 L or kg per 50 m³ per tenth of pH to lower.