Chlorine / CYA Pool Chart

CYA Pool Chart Levels

Perhaps a cornerstone element of any pool owner is understanding the relationship between the chlorine in your pool and the stabilizer you put in to protect the chlorine from the sun. Generally, the more stabilizer, the more chlorine you need to maintain its effectiveness. The charts below show the recommended relationship for outdoor residential pools.

Non-SWCG Pools

Non-SWCG Pool CYA Chart

SWCG Pools

SWCG Pool CYA Chart
* Not recommended

The shock levels shown have equivalent effective disinfecting chlorine amounts. At very high CYA levels it can be impractical to reach such high FC levels. At CYA levels over 80, a partial drain/refill to lower the CYA level is usually required before you start the SLAM.

Most saltwater chlorine generator (SWCG) pools appear to remain algae-free at a lower minimum FC level compared with the minimum FC column for manually dosed pools. This may be due to the high chlorine level within the cell.

For indoor pools we recommend CYA between 20 and 30ppm. The reasoning for using CYA indoors is quite different. For more information please ask in the comments.