Maintaining safe and clear pool water requires rigorous testing of key chemical parameters to prevent infections, equipment damage, and regulatory violations. This guide covers international testing standards (WHO, ISO), critical water quality indicators, and the best tools for accurate monitoring.
1. Free Chlorine (FC)
- Purpose: Kills bacteria and viruses (e.g., *E. coli*, *Cryptosporidium*).
- Standard Range:
- WHO Guidelines: 1–3 mg/L
- ISO 15883: 1–3 mg/L for public pools
- Risk of Deviation:
- Low: Algae growth, pathogen survival.
- High: Skin/eye irritation, corrosion.
2. pH Level
- Purpose: Optimizes chlorine efficacy and swimmer comfort.
- Standard Range: 7.2–7.8 (WHO, ISO).
- Testing Frequency: Daily for public pools.
3. Cyanuric Acid (CYA)
- Purpose: Stabilizes chlorine in outdoor pools.
- Standard Range: 30–50 ppm (ISO); >100 ppm reduces chlorine effectiveness.
4. Total Alkalinity (TA)
- Purpose: Buffers pH fluctuations.
- Standard Range: 80–120 ppm (ISO 15883).
5. Calcium Hardness
- Purpose: Prevents plaster erosion or scaling.
- Standard Range: 200–400 ppm (ISO).
1. Test Strips
- How It Works: Dip strips react with water to show color changes for 5+ parameters.
- Best For: Quick checks in residential pools.
- Limitations: ±10–15% accuracy.
2. Digital Testers
- How It Works: Electrochemical sensors measure chlorine, pH, and ORP (oxidation-reduction potential).
- Best For: Commercial pools requiring precision.
- Standards Compliance: Meets ISO 15883 lab-grade accuracy.
3. Colorimetric Kits (DPD & OTO)
- How It Works: Add reagents to water; compare colors to a chart.
- DPD Method: Measures free/total chlorine (ISO 7393-2).
- OTO Method: Detects chlorine via yellow tint (less precise).
4. Cyanuric Acid Testers
- Tools: Turbidity-based kits (e.g., Taylor K-2006) or digital meters.
- ISO Compliance: Follows ISO 15883 turbidity guidelines.
1. Sample Collection:
- Dip a clean bottle 18" below the surface; avoid return jets.
2. Free Chlorine & pH:
- Test daily using DPD tablets or digital meters.
3. Weekly Tests:
- Total alkalinity, calcium hardness, cyanuric acid.
4. Monthly Tests:
- Total dissolved solids (TDS) – keep <1,500 ppm.
Issue | Cause | Fix |
Cloudy Water | High TDS or low chlorine | Shock treatment + filtration. |
Eye Irritation | Low pH or high chlorine | Adjust pH to 7.4–7.6. |
Algae Growth | Chlorine <1 ppm | Brush walls, add algaecide. |
Adhering to ISO 15883 and WHO pool water standards is non-negotiable for preventing illnesses and maintaining equipment. By combining daily testing (strips or digital meters), staff training, and smart technology, pool operators can ensure crystal-clear, compliant water.
