Why isn't Free Chlorine decreasing if chlorinator is off?

[mikeyliny]

Using two separate testing methods including a Taylor K2006C, my FC has been around 8 ppm for over a week, in a salt water pool, despite turning off the chlorinator.

According to Dr. Google: "Sunlight depletes chlorine level, although not as fast as chemical methods. On a cloudless sunny day, 90% of the chlorine level in a pool can be destroyed in about two hours."

The pool is using a salt water chlorinator and a DE filter. A week ago, to lower the chlorine level, I turned the salt water chlorinator off. While, we have be using a robot to clean about 3x per week & the pools pump has been running most of the time, shouldnt the free chlorine level have decreased over the course of the week with the chlorinator turned off?

Taylor K2006C
FC=8
TC=8.5 (CC=0.5)
PH=7.9
ALK=90
Hardness/Calcium=90
CYA=50

My salt level is around 3200 ppm.

 

[Texas Splash]

What make/model of SWG do you have? Do you know how it receives it power (tied to pump or independently)? Can you also post a pic of your equipment pad?

 

[mknauss]

According to Dr. Google: "Sunlight depletes chlorine level, although not as fast as chemical methods. On a cloudless sunny day, 90% of the chlorine level in a pool can be destroyed in about two hours."

With no CYA.

How is your chlorinator 'turned off'? What SWCG do you have?