FC tripled in one day

[mbeck5]

Good morning. Been trouble free since April and have never enjoyed our pool more than this year. Thanks to all who helped in the transition. Yesterday my readings were:

FC - 4.0
CC - 0
PH - 7.7
TA - 50
CYA - 40
CH - 350

I added one gallon of 8.25 bleach which is what I have been adding approx 3 times a week since the weather got colder.

This morning the readings are:

FC - 14.5
CC - 0
PH - 7.8
TA - 50
CYA -40
CH - 350 I tested the FC 3 times and got the same readings. It is about 45 degrees here this morning. We keep our pool open and running year round. Using the same chemicals and leaving CYA for last based on some
cold water info I have read on here. The water is beautiful. Any idea what might have happened and what I should do? Appreciate your help.

 

[ping]

Just let the chlorine come down on its own, you will not have to add any for a little while.

My best guess is that the first test was not accurate for some reason and now the FC is a little high.

 

[duraleigh]

1 gallon of 8.25% would've raised your FC by 2.0 ppm. There is no way to get more unless you add it.

I suspect you had a math error as ping suggests.

Are you using PoolMath?

 

[swoopman]

Is it possible that the container you used to pull your water sample had any residual chlorine in it or that the water was not properly circulated before pulling the sample?

 

[JamesW]

If you accidentally used a 25 ml sample for the most recent test, that would mean that your actual fc is 5.8, which is close to the expected level based on the starting fc, pool volume, and amount of bleach added.

If you have tabs in a feeder or skimmer or a swg or a peristaltic pump adding chlorine, then that could explain the discrepancy.

 

[mbeck5]

Good morning. It appears that JamesW was correct. I must have used a 25 ml sample because this morning, my readings are back to normal. The embarrassing part is that I did the test 3 times and must have used the wrong sample size 3 times. My apologies for wasting everyones time and thank you for the support.

 

[Citizen]

lol, it happens to the best of us. Don't take it too hard.

 

[Richard320]

Good morning. It appears that JamesW was correct. I must have used a 25 ml sample because this morning, my readings are back to normal. The embarrassing part is that I did the test 3 times and must have used the wrong sample size 3 times. My apologies for wasting everyones time and thank you for the support.

Just wait until you add the wrong reagent to one of the other tests and wonder why it won't change colors even after dumping half a bottle of the third reagent in...

 

[mbeck5]

You are all very kind. Thanks again and best wishes for a great Thanksgiving.

 

[Divin Dave]

Man.... dont worry! We have all been there. LOL! We can laugh with you and not at you!


I'm glad you've enjoyed your pool more than ever before. This TFP isn't so bad is it?

Happy Thanksgiving

Good morning. It appears that JamesW was correct. I must have used a 25 ml sample because this morning, my readings are back to normal. The embarrassing part is that I did the test 3 times and must have used the wrong sample size 3 times. My apologies for wasting everyones time and thank you for the support.