What am I doing wrong

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Saltydawg15

Member
Mar 10, 2021
7
Florida
Got my new testing kit and tested the FC and got 14.5 PPM but when I went to the pool store it was 6.5 ppm. PH was fine and alkalinity I got 90 but pool store got 65.

I did the test as it is written out water to 10 ML heaping of powder mix and then counted drops until clear again.

Is there something im missing?
 
15,

You could have a testing error, but more likely the Pool Store tests are not correct. They are notoriously wrong... a lot. :mrgreen:

With a 10 ml sample each drop is .5 ppm. So, to get an FC of 14.5, you would have needed to add 29 drops, is that what you did? Or did you count 1 ppm per drop?

Pool stores reduce their TA reading by a percentage of the CYA level. Our tests do not do that, our tests are more accurate.

Trust your own tests.

Thanks,

Jim R.
 
Jimrahbe said:
Pool stores reduce their TA reading by a percentage of the CYA level. Our tests do not do that, our tests are more accurate.
Click to expand...
You'll hear it a lot: Don't trust pool store testing. Ever.

When I converted to salt (and didn't have the salt test kit yet) I had them test before and after I added the bags of salt to my pool. Of course, they wanted to run ALL of the tests and tell me what else I needed. On Saturday, they got over 100 for alkalinity and told me to add a billion gallons of acid. I ignored them, went home and added my salt. And ONLY salt. Next day, I took another sample and the alkalinity was 50.

Hadn't heard about this relationship between TA and CYA they use, but interestingly enough in the above testing, the first CYA test was like 50 and the second was 100.
 
As an ex-bench chemist it cracks me up to watch the way they titrate in stores. They over shoot all the time. I only have them test so I have a written "record" is my installer says something about my problems. My favorite trick is to fill my bottle with distilled water and take it in to the store. I stand and try not to laugh as I see the puzzled looks on their face.
 
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Jimrahbe said:
15,

You could have a testing error, but more likely the Pool Store tests are not correct. They are notoriously wrong... a lot. :mrgreen:

With a 10 ml sample each drop is .5 ppm. So, to get an FC of 14.5, you would have needed to add 29 drops, is that what you did? Or did you count 1 ppm per drop?

Pool stores reduce their TA reading by a percentage of the CYA level. Our tests do not do that, our tests are more accurate.

Trust your own tests.

Thanks,

Jim R.
Click to expand...
Yes I had 29 drops and I had two different pool store check the water and they each came within .5ppm. I have a hard time thinking that the chlorine is 14.5 PPM
 
15,

Are you using a Speed Stir type of device or swirling between drops by hand?

Let's assume for a minute, that the pool stores are spot on...

Tell us how you are chlorinating your pool and how much did you add?

What else did you recently add.

Are you holding the bottle upside down with dropper pointed at your test tube?

Are you squeezing a bunch of small drops quickly or are you letting the drops just fall off the tip?

If we assume the pool store is correct, we also have to assume you are doing something wrong or ???

Have you run another test to see if you still get 29 drops again?

Are you sure it was a 10 ml test amount and not 25 ml?

Thanks,

Jim R.
 
jliddil said:
As an ex-bench chemist it cracks me up to watch the way they titrate in stores. They over shoot all the time. I only have them test so I have a written "record" is my installer says something about my problems. My favorite trick is to fill my bottle with distilled water and take it in to the store. I stand and try not to laugh as I see the puzzled looks on their face.
Click to expand...
Chemist here, too. The owner of my local pinch a penny knows I have 20something years in the water treatment business so he generally leaves me alone when I go in to buy various parts and supplies. I cannot watch them run their testing- it makes my OCD hurt.
 
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Jimrahbe said:
15,

Are you using a Speed Stir type of device or swirling between drops by hand?

Let's assume for a minute, that the pool stores are spot on...

Tell us how you are chlorinating your pool and how much did you add?

What else did you recently add.

Are you holding the bottle upside down with dropper pointed at your test tube?

Are you squeezing a bunch of small drops quickly or are you letting the drops just fall off the tip?

If we assume the pool store is correct, we also have to assume you are doing something wrong or ???

Have you run another test to see if you still get 29 drops again?

Are you sure it was a 10 ml test amount and not 25 ml?

Thanks,

Jim R.
Click to expand...
No speed sir, just swirling by hand

Have a salt system set at the lowest level which was off all day the day prior as we were making some plumbing changes.

Nothing added recently

Hold the bottle perpendicular to the tube

One drop at a time

Ran 3 test all with similiar numbers.
 

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