How did the CYA levels get so high in my pool ?

[wetone]

CYA what causes high levels ?

Thanks

 

[harleysilo]

Hi! CYA gets into your pool by the use of stabilized chlorine products, or by adding it directly (it is also caused Stabilizer).

How do you chlorinate your pool? How did you test for CYA?

 

[257WbyMag]

Unlike chlorine, CYA is not "used up". The levels will continue to rise unless it is physically removed by the backwash process or by splash out.

 

[dattia]

CYA is something that has been added to your water as stabilizer or conditioner. It can also add up over time through the use of Chlorine Tablets, as they are stabilized. Typically, CYA does not leave your water on its own by evaporation or breakdown... high levels of CYA must be removed by replacement of water. While it is very important to have CYA in your water, having too much can start to work against you in your efforts to maintain a clear pool.

 

[wetone]

Are high CYA levels dangerous ? to swim in ..

 

[dattia]

No, I don't believe so... just creates a high chlorine demand.

 

[chem geek]

CYA increases over time in a pool if you are using stabilized chlorine products, Trichlor pucks/tabs (or powdered "shock") or Dichlor granular (sometimes also sold as "shock"). For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm. So it can rise pretty quickly if you don't have a lot of water dilution.

The main problem with the higher CYA is that it reduces the active chlorine level allowing algae to grow faster than chlorine can kill it. You can compensate for this by raising the FC level as the CYA level changes (i.e. follow the Chlorine/CYA Chart), but when the CYA gets very high (above 80 ppm especially) it gets risky because IF you let the chlorine level get too low and then need to shock the pool to kill any algae that gets started, it will take a LOT of chlorine to do this.