Cyanuric acid now available as a SensoStick – why do I measure cyanuric acid?

Water treatment in outdoor pools with organic, stabilised chlorine is particularly popular. The carrier substance is cyanuric acid. This type of water disinfection has several advantages. Firstly, it is easy and safe for the user to handle. The commercially available, compressed tablets are simply added to the skimmer or dosing float and dissolve. Granules are also available, which are sprinkled onto the water surface and dispersed.

However, the greatest advantage compared to inorganic chlorine is its relative resistance to strong sunlight and UV light. However, depending on the concentration, cyanuric acid binds part of the chlorine measured with the DPD indicator, which is then no longer available for disinfection. We therefore recommend a maximum concentration of cyanuric acid of 50 mg/l with a chlorine content of between 1.0 and 3.0 mg/l, measured with DPD. The cyanuric acid should be measured weekly using the LILIAN photometer in conjunction with the SensoStick “CYS”. The reduction is only possible with filling water (usually drinking water quality) by diluting the pool water.

With LILIAN, the measurement of cyanuric acid is now also possible! You just need to make sure that you are using the latest app and the latest firmware. You can find the app in the Appstore and you can download the firmware from our homepage under Downloads. How the firmware update works is described in a video under “Videos” on our homepage. Your existing LILIAN can measure the new parameters just as easily!