Combined Chlorine

[dschribs]

One thing I never understood.... A reading of. 5 combined chlorine is acceptable to end a SLAM. But if I am getting .5 combined chlorine after testing, doesn't that mean that there is actually something in the pool using up chlorine?

Shouldn't combined chlorine be at zero???

 

[Donldson]

Of course there is something in the pool using up chlorine, it's an open body of water. Always some organic matter falling in to it. That's why you need to have the chlorine level at or above the minimum at all times, because otherwise whatever falls in the pool could get a foothold and grow.

A little CC is nothing to worry about, the chlorine is doing its job. A lot of CC means it is doing its job and falling behind, indicative of a problem.

 

[Richard320]

In a perfect world, yes, CC will be at zero. In reality, if something organic starts reacting with the chlorine, you get combined chloramines. It could be sweat, snot, urine, or worse. It could even be refill water, since some water companies use chloramines to prevent pipe corrosion.