How to test for Cyanuric Acid (CYA) levels

Whether you call it cyanuric acid, stabilizer, or sunscreen for your pool, CYA is one of the critical elements that help keep your pool clear and healthy. UV light (which Australia has in over-abundance) causes the depletion of free chlorine. Without CYA, you have to add more chlorine to keep your pool healthy, or run your salt-water generator longer and harder. Adding the correct amount of CYA will therefore save you lots of money – but be careful! Adding too much CYA will cause major headaches as it will prevent your high levels of free chlorine from working.

The instructions on the sides of our kit are simplified reminders of the procedure for advanced users (see image below). These are the extended instructions for the CYA Detection Test Kits, that give you all the nitty gritty details on how to test your pool for CYA levels.


  1. K50847_2Rinse the CYA mixing tube with pool water.
  2. Fill the CYA mixing tube with pool water to the mark indicated. Allow the water to come to room temperature if pool is cold.
  3. Fill the CYA mixing tube to the mark indicated with CYA Detection Reagent. Replace the lid on the reagent immediately to extend the life of your kit.
  4. Mix the CYA mixing tube thoroughly for 30 seconds.
  5. Find a well lit position. Hold the CYA viewing tube at waist level and, looking down into the tube, slowly pour the contents of the mixing tube in until the logo at the base of the tube disappears. Alternatively, use the included droppers to control the dispensing rate until the logo disappears.
  6. Note: The accuracy of the test kit will depend on the brightness of the ambient light in which the test is taken. Strong Australian sunlight may cause an underestimate of your CYA level. Dim interior lighting may cause you to overestimate your CYA level.
  7. Look at the scale on the side of the CYA viewing tube. The water level on this scale indicates your CYA level.
  8. Note: This kit is accurate between 30ppm and 100ppm of CYA. If your levels read above 100 ppm, you will need to dilute your sample to obtain an accurate reading. Mix equal parts of pool water and tap water, test this mix, and multiply your result by two. If your test is below 30ppm, you will need to add more CYA to your pool, and then retest to obtain an accurate reading. 
  9. Note: The mix of pool water to CYA detection Reagent is 50:50. If you need to adjust the amount of water/reagent mix used, just combine equal parts pool water with CYA Detection Reagent
  10. Pour the contents of the viewing tube back into the mixing tube. Repeat steps 5 and 6 as often as necessary to obtain confidence in your results.
  11. Dispose of the sample safely. Do not pour the sample and chemicals back into the pool, instead pour down the sink with some running water.
  12. Rinse the sample tube with tap water and store in a cool, dark, and dry place.


Want a printable version of these instructions? We have you covered!

Download (CYA_Test_Kit_Instructions.pdf, PDF, 488KB)