Limitation of Cyanuric acid content for swimming pool.

For the swimming pool, water sanitation is the most concerned thing of the friends who love swimming.

In order to ensure the safety of water quality and the health of swimmers, disinfection is one of the common treatment methods of swimming pool water. Among them, sodium dichloroisocyanurate (NaDCC) and trichloroisocyanuric acid (TCCA) are the most widely used disinfectants.

NaDCC or TCCA will produce hypochlorous acid and cyanuric acid when contacting with water. The presence of cyanuric acid has a double-sided impact on the chlorination disinfection effect.

On the one hand, cyanuric acid will slowly decompose into CO2 and NH3 under the action of microorganisms or ultraviolet rays. NH3 reacts reversibly with hypochlorous acid to store and slow release hypochlorous acid in water, so as to maintain its concentration stable, so as to prolong the disinfection effect.

On the other hand, the slow-release effect also means that the concentration of hypochlorous acid playing the role of disinfection will be relatively reduced. In particular, with the consumption of hypochlorous acid, the concentration of cyanuric acid will gradually accumulate and increase. When its concentration is high enough, it will inhibit the production of hypochlorous acid and cause “chlorine lock”: even if a high concentration disinfectant is put in, it can not produce enough free chlorine to give full play to the due disinfection effect.

It can be seen that the concentration of cyanuric acid in swimming pool water has an important impact on the effect of chlorine disinfection. When using NaDCC or TCCA for swimming pool water disinfection, the concentration of cyanuric acid must be monitored and controlled. The limit requirements for cyanuric acid in the current relevant standards in China are as follows:

Limitation of Cyanuric acid content for swimming pool water:

Source: Water quality standard for swimming pool (CJ / T 244-2016)