The Pool School says to perform first at night, 30 minutes after sundown. Is the point to perform the test when there's been no direct sunlight on the pool for 30 minutes? I have a tree line that puts my pool in shade about 4 PM. Could I not do the evening side of the OCLT at 4:30PM??
Timing of OCLT for FC
- Thread starter Curmudgeon10
- Start date
Welcome to the forum :lol:
Keeping your posts in one thread will get you better answers and help us better understand your questions.
The purpose of the OCLT is to determine if you have properly shocked the pool. So, when you pool water is crystal clear, perform the FAS/DPD test that evening. Note your FC and CC results. CC's need to be .5 or less. If they are not, you need to maintain FC at chock value and you can stop the OCLT.
Let's say, however, your water is clear and your CC's are .5ppm or less....you have met 2 odf the three criteria.
Now you want to see how much chlorine you will lose during the hours of darkness. By eliminating loss of FC from the sun, any remaining loss can be attributed to algae still in your pool. Loss of 1ppm or greater (during the hours of darkness) of FC is too much so you fail the OCLT and should continue to maintain shock level.
Or, more simply, the purpose of the OCLT is to measure the FC loss during dark hours.
Keeping your posts in one thread will get you better answers and help us better understand your questions.
The purpose of the OCLT is to determine if you have properly shocked the pool. So, when you pool water is crystal clear, perform the FAS/DPD test that evening. Note your FC and CC results. CC's need to be .5 or less. If they are not, you need to maintain FC at chock value and you can stop the OCLT.
Let's say, however, your water is clear and your CC's are .5ppm or less....you have met 2 odf the three criteria.
Now you want to see how much chlorine you will lose during the hours of darkness. By eliminating loss of FC from the sun, any remaining loss can be attributed to algae still in your pool. Loss of 1ppm or greater (during the hours of darkness) of FC is too much so you fail the OCLT and should continue to maintain shock level.
Or, more simply, the purpose of the OCLT is to measure the FC loss during dark hours.
Indirect sunlight in the early evening can still lower the FC level, so you might get a false indication of algae when there really isn't any if you do the first test too early. Usually this isn't a big deal, and if you still pass the test then you are fine. But if you fail the test, it won't be completely obvious why as it could still have been late afternoon indirect sunlight.
Thanks for the answers. Based on the topology of my site, I can do the evening test at least an hour before sundown, and there won't be any sunlight of any kind --- direct or indirect --- to distort results.