I. Importance and meaning of residual chlorine
Swimming pools are places for people’s leisure and entertainment, so their water quality must be kept clean and hygienic to ensure the health and safety of swimmers. As a key indicator of swimming pool water quality, residual chlorine plays a vital role. The content of residual chlorine can reflect the cleanliness of the swimming pool, as well as the disinfection and sterilization effect in the swimming pool. If the residual chlorine content is insufficient or too high, it may pose a potential threat to the health of swimmers. Therefore, the measurement of residual chlorine is a very important task for swimming pool management and maintenance.
II. Classification of residual chlorine content in swimming pools
The residual chlorine content in swimming pools is divided into two categories, namely free residual chlorine and combined residual chlorine. Free residual chlorine refers to chlorine molecules in the swimming pool that are not combined with organic matter or bacteria. They are the available chlorine in the swimming pool water. Combined residual chlorine refers to compounds formed after the reaction between chlorine molecules and organic matter or bacteria. They no longer have the ability to disinfect and sterilize. Therefore, swimming pool managers need to pay attention to the free residual chlorine in the swimming pool water to ensure the safety and hygiene of water quality.
III. The necessity of daily residual chlorine testing
A. Requirements of the health supervision department
The health supervision department has put forward strict requirements for the water quality and safety of swimming pools, including daily testing of residual chlorine levels. This is to ensure the health and safety of swimmers, so pool managers must comply with this rule.
B. Pool Manager Responsibilities
Swimming pool managers not only need to meet the requirements of the health supervision department, but also fulfill their own responsibilities to ensure that the water quality of the swimming pool meets standards. Daily testing of residual chlorine levels is one of the managers’ responsibilities, as this can help them detect problems in time and take necessary measures to maintain swimming pool water quality.
IV. Residual chlorine detection method
Pool managers can choose from different chlorine testing methods, depending on their needs and budget. Here are some commonly used methods:
A. Simple DPD method
The simple DPD method is currently a relatively accurate method for on-site detection of residual chlorine. It uses the residual chlorine quick test box, which is a test kit specially used for swimming pool water quality testing, and uses the DPD method to detect residual chlorine. The residual chlorine rapid test kit includes a cuvette and two bottles of DPD tablets. The test range is usually between 0-1.0mg/L. The method of use is relatively simple, including sampling, adding developer/paper and colorimetric steps. However, the testing accuracy of this method is low and can only provide an approximate range of residual chlorine rather than an accurate value.
B. OTO method
The OTO method is another commonly used residual chlorine detection method that can quickly determine the concentration of total chlorine, residual chlorine and ozone in water. The test range is usually between 0.5-10mg/L, the test effect is obvious, and the test cost is low. This method is suitable for residual chlorine testing in swimming pools, footbaths, etc. The method of use is relatively simple. You only need to take a sample, add OTO residual chlorine test solution and shake it well. Then judge the concentration of residual chlorine based on the color development results and color card. However, like the simple DPD method, this method has lower testing accuracy.
C. DPD method photometry
In terms of swimming pool water quality testing, the DPD photometric method is considered the most accurate and reliable method. It uses a DPD photometer combined with tablets for testing, which can provide accurate numerical results, accurate to two digits after the decimal point. This method is very simple and suitable for both indoor and outdoor pools. The usage method includes taking a sample, adding DPD1 tablet reagent, pressing the FCL key, etc. The test results can be obtained in a short time.
V. Water quality online monitor
A. Installation and functionality
In order to more conveniently monitor the residual chlorine content of the swimming pool, the swimming pool manager can choose to install an online water quality monitor. These online monitors can remotely monitor the residual chlorine, pH value, turbidity, ORP (oxidation reduction potential), temperature and other parameters of the swimming pool in real time. They are often installed in swimming pool systems and provide continuous monitoring data.
B. Advantages of real-time remote monitoring
Through the online water quality monitor, the swimming pool administrator can check the water quality of the swimming pool at any time without going to the site in person. This helps detect abnormal chlorine levels or other water quality issues in a timely manner so that necessary measures can be taken faster. In addition, online monitoring can also help managers track water quality trends and better manage swimming pools.
C. Response to emergencies
When emergencies occur, such as residual chlorine being too high or too low, the water quality online monitor can provide real-time alerts, allowing managers to respond quickly and take necessary measures to ensure the safety of the swimming pool. This ability is essential to avoid potential risks and protect swimmers’ health.
VI. Adjust residual chlorine level
A. Neutralization of excessive residual chlorine
When the swimming pool self-checks and the residual chlorine level is too high, a chlorine neutralizer can be used to quickly neutralize the residual chlorine. Taking Creed chlorine neutralizer as an example, each dose of 1 gram can reduce the chlorine content by 1mg/L. Therefore, based on the actual residual chlorine content, the required dose can be calculated and evenly distributed into the pool water.
B. Increase in excessively low residual chlorine
When the residual chlorine content is too low, you can consider adding compound disinfection tablets to increase the effective chlorine content in the water. Every time 2 grams of Fuxiao Qing disinfectant are added, the effective chlorine in the water can be increased by 1.1mg/L. The dosage should be adjusted according to the actual water quality to ensure that the residual chlorine reaches the safe range of 0.3-1.0mg/L.
VII. Conclusion
In swimming pool management, the detection and maintenance of residual chlorine is a key link to ensure clean water quality and safety of swimmers. Different residual chlorine detection methods are suitable for different situations, but attention should be paid to their testing accuracy and limitations. The water quality online monitor provides managers with a more convenient monitoring method and can realize real-time remote monitoring to respond to emergencies. In addition, managers should know how to adjust residual chlorine levels to keep water quality within safe limits. In summary, residual chlorine detection and maintenance are crucial to the safety and hygiene of swimming pools and need to be fully valued and managed.