<– Back To Pool School

CYA / Chlorine Chart

CYA – CHLORINE CHART

Perhaps a cornerstone element of BBB 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 are the recommended relationship.

NON-SWCG POOLS

(CYA) CONDITIONER MINIMUM FC TARGET FC SHOCK FC
20 ppm 2 ppm 3 ppm 10 ppm
30 ppm 2 ppm 4 ppm 12 ppm
40 ppm 3 ppm 5 ppm 16 ppm
50 ppm 4 ppm 6 ppm 20 ppm
60 ppm 5 ppm 7 ppm 24 ppm
70 ppm 5 ppm 8 ppm 28 ppm
80 ppm 6 ppm 9 ppm 31 ppm
90 ppm 7 ppm 10 ppm 35 ppm
100 ppm 7 ppm 12 ppm 39 ppm

SWCG POOLS

(CYA) CONDITIONER MINIMUM FC TARGET FC SHOCK FC
50 ppm 3 ppm 4 ppm 24 ppm
70 ppm 3 ppm 5 ppm 28 ppm
80 ppm 4 ppm 6 ppm 30 ppm

The shock levels shown have equivalent effective disinfecting chlorine amounts. At high CYA levels it may be impractical to use such high FC levels, lower FC levels are often sufficient though they take longer to kill algae. At very high CYA levels, over 80, a partial drain/refill to lower the CYA level is usually required.

Most saltwater chlorine generator (SWG) pools appear to prevent algae at a lower minimum FC level compared with the minimum FC column for manually dosed pools.