For online monitoring of swimming pool residual chlorine, under what circumstances can a membraneless residual chlorine sensor be used?

Accurate measurement of residual chlorine levels in swimming pools is crucial to safeguarding swimmers’ health. YuanGan Technology has launched DP film-free chlorine residual sensor and DPM membrane-covered chlorine residual sensor. Both of these two residual chlorine sensors have been widely used in online monitoring of residual chlorine in swimming pools.

In the application scenario of online monitoring of residual chlorine in swimming pools, it is first recommended to use a membrane-covered residual chlorine sensor. However, because membraneless residual chlorine sensors are cheaper and relatively easy to use, they are favored by many users. So, in the application scenario of online monitoring of residual chlorine in swimming pools, under what circumstances can a membraneless residual chlorine sensor be used?

In the application scenario of online monitoring of residual chlorine in swimming pools, the following conditions need to be met:

The disinfectant is sodium hypochlorite or calcium hypochlorite

When the cyanuric acid content in the swimming pool is high, the measured value of the membraneless residual chlorine sensor will drop significantly due to the chlorine locking effect of cyanuric acid. Therefore, for swimming pools disinfected with trichloroisocyanuric acid, we recommend the use of membrane-covered residual chlorine sensors, but do not recommend the use of film-free chlorine sensors.

When sodium hypochlorite or calcium hypochlorite is used as the disinfectant, cyanuric acid will not appear in the swimming pool, and a membraneless residual chlorine sensor can be used.

Low urea content

In order to reduce costs, some swimming pool owners do not replace new water in the swimming pool for a long time or the amount of new water replacement is seriously insufficient, which will cause the urea content in the swimming pool to increase. Urea will be converted into ammonia nitrogen and combine with hypochlorous acid to form organic chlorines such as monochloramine and dichloramine (also known as combined chlorine). However, the membraneless residual chlorine sensor does not respond to organic chlorine. When the organic chlorine content is high, the output value of the membraneless residual chlorine sensor will be lower than the measurement value of the DPD or OTO reagent method.

Therefore, if you want to use a membraneless residual chlorine sensor, the urea content of the swimming pool needs to be low so that the measured value is comparable to the reagent method.

Summary

In the online monitoring of residual chlorine in swimming pools, when the disinfectant is sodium hypochlorite or calcium hypochlorite, the urea content is low, and regular maintenance and calibration can be done, a membraneless residual chlorine sensor can be used, which can not only ensure the accuracy of measurement, but also take advantage of its low price and ease of use.

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