Disinfection process analysis of swimming pool national standards

Puzzle-solving Classroom: Protecting Swimming Pool Safety - Disinfectant Selection and Interpretation of Water Quality Standards (December 2025 Edition)

In the hot summer, the swimming pool has become an important place for people to cool off and have fun. To ensure the safety of swimming pool water quality, it is necessary to scientifically select disinfectants and strictly implement the latest standards. Chongqing YuanGan Technology combines the requirements of national standards such as the upcoming GB/T 18204.2-2025 "Hygiene Inspection Methods for Public Places" to provide you with professional swimming pool disinfection guidance.

In the hot summer, the swimming pool has become an important place for people to cool off and have fun. To ensure the safety of swimming pool water quality, it is necessary to scientifically select disinfectants and strictly implement the latest standards. Chongqing YuanGan Technology combines the requirements of national standards such as the upcoming GB/T 18204.2-2025 "Hygiene Inspection Methods for Public Places" to provide you with professional swimming pool disinfection guidance.

1. Key points for selecting and using swimming pool disinfectants

1. Chlorine disinfectants - the mainstream choice

• Sodium hypochlorite (liquid) Dosing method: Accurate dosing through metering pump Advantages: Safe operation, widely used Disadvantages: The solution is unstable and needs to be properly stored

Sodium hypochlorite (liquid)

• Dosing method: precise dosing through metering pump
• Advantages: safe operation, wide application
• Disadvantages: The solution is unstable and needs to be stored properly
• Calcium hypochlorite (solid) Dosing method: Add through metering pump after dissolution Advantages: Good stability, easy to store Notes: May increase water hardness, long-term use needs to prevent scaling

Calcium hypochlorite (solid)

• Dosing method: add through metering pump after dissolution
• Advantages: good stability, easy to store
• Note: water hardness may increase, long-term use requires prevention of scaling
• Trichloroisocyanuric acid (tablets/granules) Dosing method: Use a special automatic dosing device Advantages: Sustained release effect, easy to use Special reminder: Pay attention to the impact of cyanuric acid accumulation on the disinfection effect

Trichloroisocyanuric acid (tablets/granules)

• Dosing method: Use special automatic dosing device
• Advantages: sustained release effect, easy to use
• Special reminder: Pay attention to the impact of cyanuric acid accumulation on disinfection effect

2. Other disinfection methods

• Bromine disinfectant is suitable for indoor heated swimming pools. It feels more comfortable and has less irritation to the eyes.

Bromine disinfectant

• Suitable for indoor heated swimming pools
• More comfortable to the body and less irritating to the eyes
• Ozone/UV must be used in conjunction with chlorine disinfectants as an auxiliary disinfection method

Ozone/UV

• Must be used in conjunction with chlorine disinfectants
• As an auxiliary means of disinfection

2. Core requirements of water quality standards

According to GB 37488-2019 "Hygiene Indicators and Limit Value Requirements for Public Places" and industry practice, key indicators of swimming pool water quality should be controlled within the following ranges. The detection methods of some of the indicators will be based on the new version of the inspection standards implemented on December 1, 2025:

Main water quality indicators and testing requirements

Please note: The GB/T 18204.2-2025 standard will be released on May 30, 2025, and will be officially implemented on December 1, 2025, replacing GB/T 18204.2-2014. This standard is an inspection method standard, which mainly stipulates the measurement methods of chemical indicators, including the measurement of urea and redox potential in swimming pool water.

Other requirements:

• The foot immersion disinfection pool should maintain an effective residual chlorine concentration
• The circulating filtration system should remain in normal operation
• When water quality is abnormal, timely measures should be taken

3. Standard implementation key points and testing requirements

1. Description of important standard status

• GB 37488-2019: It is a currently valid mandatory standard that stipulates the limit requirements for health indicators in public places. According to information from the National Standard Information Public Service Platform, the standard has been planned to be updated (plan number: 20250063-Q-628).
• GB/T 18204.2-2025: For the recommended national standard that will be implemented soon, it stipulates the testing methods for health indicators. This standard is proposed and administered by the National Administration of Disease Control and Prevention.

2. Main changes in the new inspection method

• Free residual chlorine: adjusted from 0.2-1.0 mg/L to 0.3-0.8 mg/L (the upper limit is reduced by 20%)
• Combined residual chlorine: adjusted from ≤0.4 mg/L to **≤0.3 mg/L** (limit tightened by 25%)
• ORP value: New requirement **≥650 mV**

3. Specification of testing methods

• DPD Spectrophotometry: Laboratory Arbitration Method

DPD Spectrophotometry: Laboratory Arbitration Method

• Electrochemical sensor method: on-site rapid detection response time requirement: ≤30 seconds indication error requirement: ±0.05 mg/L calibration requirement: regular calibration with standard solution

Electrochemical sensor method: rapid on-site detection

• Response time requirement: ≤30 seconds
• Indication error requirement: ±0.05 mg/L
• Calibration requirements: Calibrate regularly with standard solution

4. Sampling specifications

• Sampling location: 30 cm below the water surface, an appropriate distance from the pool wall
• Sampling points: Mix water samples at multiple points
• Sample preservation: timely testing to ensure accuracy of results

4. Intelligent monitoring solutions

[YuanGan Technology Online Monitoring System]

• Suggestions for sensor selection: Film-coated residual chlorine sensor: Strong anti-interference, suitable for most swimming pools Exposed sensor: Only for professional venues with stable water quality Multi-parameter integrated monitoring: Simultaneously monitors residual chlorine, pH, ORP

Sensor selection suggestions

• Film-coated residual chlorine sensor: strong anti-interference, suitable for most swimming pools
• Exposed sensors: only in professional venues with stable water quality
• Multi-parameter integrated monitoring: simultaneously monitor residual chlorine, pH, and ORP
• System functions: real-time data transmission and over-standard alarm, automatic generation of monitoring reports, remote monitoring and management

System functions

• Real-time data transmission and over-standard alarm
• Automatically generate monitoring reports
• Remote monitoring and management

5. Daily management specifications

Operation management requirements:

• Establish complete disinfectant usage records
• Calibrate monitoring equipment regularly
• Develop an emergency plan for abnormal water quality
• Strengthen operator training

Equipment maintenance requirements:

• Regular maintenance of circulation filtration system
• Regular inspection of dosing equipment
• Monitoring sensors are regularly calibrated

Important reminder

• GB/T 18204.2-2025 will be officially implemented on December 1, 2025
• It is recommended to update monitoring equipment and management processes in advance to adapt to new inspection method requirements.
• All inspection records must be kept completely for future reference
• Please pay attention to the revision progress of GB 37488-2019 and follow up on the latest limit requirements in a timely manner

Conclusion

Scientific selection of disinfectants, strict implementation of standard requirements, and accurate monitoring methods are the keys to ensuring the safety of swimming pool water quality. With the implementation of the new version of inspection method standards, higher requirements have been put forward for swimming pool water quality monitoring.

Chongqing YuanGan Technology Co., Ltd. provides complete swimming pool water quality monitoring solutions that meet the latest standards, including high-precision sensors, intelligent monitoring equipment and digital management platforms, helping swimming pool operators achieve accurate and efficient water quality management.

—— Chongqing YuanGan Technology Co., Ltd., the water quality safety sensing expert around you

Attached: Reference standards

• GB 37488-2019 "Hygienic Indicators and Limit Requirements in Public Places" (currently effective)
• GB/T 18204.2-2025 "Hygiene Inspection Methods for Public Places Part 2: Chemical Indicators" (implemented on 2025-12-01)
• GB 38850-2020 "Disinfectant Raw Material List and Prohibited and Restricted Substances"
• EN 15796:2022 "Chemicals for swimming pool water treatment - Calcium hypochlorite"