Chlorine 25ppm and not dropping

[BC78]

I was running my SWG at the recommended poolmath app numbers and chlorine was off the charts. It’s been a couple of weeks now and I have left the SWG off but chlorine is not dropping. It’s been stuck at 25. I have used 3 different test kits and they all give the same reading. Combined chlorine is less than 0.5ppm and CYA is a hair lower than recommended. Why is my free chlorine not dropping?

 

[mknauss]

Cloudy? Shaded? This time of year FC can stick for quite some time depending on location.

 

[BC78]

Cloudy? Shaded? This time of year FC can stick for quite some time depending on location.

Crystal clear, in the sun for at least 8-9hrs of the day. Temps have been anything from low 30’s to high 70’s the last few weeks. Maybe only an inch of rain but I have added a few inches of water myself to keep it topped up.

 

[mknauss]

Interesting. Keep testing FC every few days. Be sure you are using a 10ml sample, one scoop of powder, each drop of reagent to clear is 0.5 ppm. So you are using 50 drops for 25 ppm.

 

[BC78]

Interesting. Keep testing FC every few days. Be sure you are using a 10ml sample, one scoop of powder, each drop of reagent to clear is 0.5 ppm. So you are using 50 drops for 25 ppm.

I thought I was going crazy when I first tested as I was using so many drops and the color stayed red. I thought there’s no way it can be right so I tested with the other kit and same deal. I’m testing again tomorrow so will see if it’s dropped any and report back.

 

[generessler]

I'm in Chapel Hill. This time of year mine drops 0.5 ppm every 2-3 days with CYA 70.