Pool Chemical Calculator — UK

Metric by default: grams and kg alongside oz/lbs. ppm = mg/L.

Step 1: Pool Volume

Pool Volume (litres)*

Don't know your volume? Use our Volume Calculator first

Calculate pool volume

Step 2: Current Test Readings

ppm = mg/L (same numbers, UK labels read mg/L). Doses show metric + imperial.

pH Level

Ideal range: 7.2 - 7.6

Free Chlorine (mg/L)

Ideal range: 1.0 - 3.0 mg/L

Total Alkalinity (mg/L)

Ideal range: 80 - 120 mg/L

Calcium Hardness (mg/L)

Ideal range: 200 - 400 mg/L

Cyanuric Acid / Stabilizer (mg/L)

Ideal range: 30 - 50 mg/L (outdoor pools)

Step 3: Your Target Levels

Defaults are common ideal midpoints — override to match your provider's recommendations.

Target pH

Target FC (mg/L)

Target TA (mg/L)

Target CH (mg/L)

Target CYA (mg/L)

Water Chemistry Guide

pH (7.2-7.6)

Affects chlorine effectiveness and swimmer comfort

Free Chlorine (1-3 mg/L)

Kills bacteria and algae to keep water sanitized

Total Alkalinity (80-120)

Stabilizes pH and prevents fluctuations

Calcium (200-400)

Prevents surface damage and cloudiness

Cyanuric Acid (30-50)

Protects chlorine from UV degradation

Safety First

• Always add chemicals to water, never water to chemicals
• Wear protective gloves and eyewear
• Work in a well-ventilated area
• Never mix different chemicals together
• Store chemicals in a cool, dry place

Testing Tips

• Test water 2-3 times per week during swim season
• Test in the morning before the sun affects readings
• Collect water sample 12-18 inches below surface
• Wait 4-6 hours after adding chemicals before retesting