OCLT: can I test it when overcast?

[DeptOfMeteors]

How reliable is testing your FC for the lost test when it's overcast. I've been doing a SLAM for the last few days, and my FC was well above the recommended 12ppm, (not sure how. PoolMath told me to put even more jugs in than I did) but last night, when it was completely overcast, I tested it at 12.5ppm. The clouds never went away and this morning it was closer to 8ppm. However, I don't see any algae forming, the water is clear and the CC is down to 0.5ppm.
Another explanation for the FC results is that I'm still working on my testing skills. See: Questioning the science of the volume of a liquid drop. It seems as though I was overrating my FC before, but I'm quite confident it was well over 12ppm for a day or two.

 

[ajw22]

If you started the night at 12ppm and had 8ppm in the morning you failed the Overnight Chlorine Loss Test and need to continue the SLAM Process. Even with clear water and 0.5 CC. You still have algae in the clear water.

Clouds do not make a difference in the Overnight Chlorine Loss Test

When you are doing a Overnight Chlorine Loss Test best to test your FC 30 minutes after you add the chlorine at the start of the night and see what you really got and not rely on PoolMath calculations.

 

[Mdragger88]

I am not following.. the Overnight Chlorine Loss Test is done after it gets dark & before sunrise.
There should be no clouds involved.

 

[DeptOfMeteors]

The idea is there if there's no sun, chlorine can't be lost to sunlight. So overcast skies would make for attractive opportunities for non-morning people.

 

[proavia]

Even when it's cloudy during daylight hours, the sun is still there.
UV will still penetrate clouds and could use up chlorine. This will skew the results.
For the Overnight Chlorine Loss Test - whether cloudy or not - test after official sundown and then before official sunrise. Many will do it after last light and before first light - in other words, when its dark outside.

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