What does CC combined Chlorine tell us?

[Jsf721]

Can someone explain what the combined chlorine means and how it gets “high”. From my understanding high CC is a bad thing.

I was upset mine was only .5 but then ready zero is better.

 

[ajw22]

Start with…

CC - Further Reading

www.troublefreepool.com

CC of 0.5 to 1 is indicative of normal sanitation by the chlorine. Over 1 may indicate an algae problem and a Overnight Chlorine Loss Test should be done.

 

[jeffchap]

From Pool Care Basics:

"Combined chlorine is an intermediate breakdown product created in the process of sanitizing the pool. CC causes the “chlorine” smell many people associate with chlorine pools. If CC is above 0.5ppm, you should SLAM your pool. CC indicates that there is something in the water that the FC is in the process of breaking down. In an outdoor pool, CC will normally stay at or near zero as long as you maintain an appropriate FC level and the pool gets some direct sunlight."