How long after chlorine can you test?

[ramirez41]

How long after adding chlorine can you test the level? My pump runs for about a hour after I add chlorine and then shuts off for the night.

My water is clear, but I have been adding enough chlorine to raise my levels to 9 at night. By the next night when I test it is between 5-6 ppm. I would expect lose 1.5-2ppm each day from the sun. We have had some storms come through at night, but I don't notice much of a difference in my water level. Bather load has been 2-4 people for no more 2 hours a day and it is mostly just 2, today it was none. Does it seem right that I would lose that much chlorine each day or am I maybe fighting algae that isn't seen yet? I haven't needed to vacuum the pool in a week because there is nothing to vacuum up beside 2-3 leaves that I just pick up by hand.

 

[proavia]

FC can be retested 15-30 minutes after adding liquid chlorine with the pump running.

Algae can be invisible to the naked eye - especially in its early stages.
If in doubt whether your FC usage is "normal" or not, do the Overnight Chlorine Loss Test.

 

[ramirez41]

FC can be retested 15-30 minutes after adding liquid chlorine with the pump running.

Algae can be invisible to the naked eye - especially in its early stages.
If in doubt whether your FC usage is "normal" or not, do the Overnight Chlorine Loss Test.

Thank you. I hear more thunder so the over night test will have to wait another night. I am hoping it is just from the storms and not algae. However the past 3 years I have gotten pink slim around the end of July or a couple weeks into August. That problem lead me here so hoping to avoid that this year.

 

[ramirez41]

I definitely hit 9ppm when I just retested after my add.

 

[proavia]

I definitely hit 9ppm when I just retested after my add.

Great - retest in the AM before the sun comes up.

 

[ramirez41]

Great - retest in the AM before the sun comes up.

My level this morning is 7.5ppm for chlorine however we did get at least a half inch of rain last night so I am thinking I need to redo the overnight test again when we don't get rain. I am debating on adding more chlorine this morning closer to the time of when my pump would normally turns on.

 

[mknauss]

Rain has little effect on water chemistry unless you get a foot or more of rain in a short time overflowing the pool.

As long as the pump was run for 30 minutes prior to the water sample being taken, the test is good.

 

[ramirez41]

Rain has little effect on water chemistry unless you get a foot or more of rain in a short time overflowing the pool.

As long as the pump was run for 30 minutes prior to the water sample being taken, the test is good.

I should run the pump 30 mins in the morning before testing? My pump was not running yet.

 

[mknauss]

I should run the pump 30 mins in the morning before testing? My pump was not running yet.

It is a good practice to run pump prior to sampling.