Pool Store Test Results Different From Mine

[coachdad]

Pool store PH results today was 6.9, my result was ~7.6 with home test kit. Reagent is less than a month old.

Pool store says salt is 3200, same as last test 3 weeks ago before several inches of rain and no added salt. I do not have a home salt test.

My FAS/DPD was 4.5, pool store says 4.3.

The confusion is that it seems their chlorine test is matching mine, PH test is drastically different and salt is obviously wrong unless the copious rain was salty.

Is this the point where I completely distrust their results and go with mine, or go with their computer test?

 

[FlappyLipps]

Is this the point where I completely distrust their results and go with mine?

Yes

 

[V___25]

Is this the point where I completely distrust their results and go with mine, or go with their computer test?

This is the point where you never go back to a pool store again. Assuming you have one of the 2 recommended test kits, you trust your own from this point forward.

 

[drsipe]

My brother-in-law took two sample bottles from his pool at the same time and took them to one of the big name pool stores and had them tested, telling the employee that one was from his pool and one was from the neighbors pool. The test results did NOT match, almost all the results differed, and CYA was the worst, over 30 ppm difference between them.

I don't think most pool stores are trying to give bad results, they are busy, in a hurry, are not careful with measuring samples, and are sloppy with cleaning test equipment. I know when I had taken samples to the pool store, it was usually someone very young doing the testing and I'm sure he had all of about 5 minutes of training.

 

[proavia]

Pool store PH results today was 6.9, my result was ~7.6 with home test kit. Reagent is less than a month old.

Pool store says salt is 3200, same as last test 3 weeks ago before several inches of rain and no added salt. I do not have a home salt test.

My FAS/DPD was 4.5, pool store says 4.3.

The confusion is that it seems their chlorine test is matching mine, PH test is drastically different and salt is obviously wrong unless the copious rain was salty.

Is this the point where I completely distrust their results and go with mine, or go with their computer test?

Welcome to TFP!

What test kit are you using?
As has been mentioned, pool store "free" testing is unreliable and inconsistent.

To accurately measure salt content, get a Taylor K-1766 salt test kit.

Fill out your signature with pool, pool equipment (including manufacturers and model numbers) and test kit info.
This assists us in providing help specific to your pool without needkng to ask you each time.

https://www.troublefreepool.com/account/signature

 

[Oly]

I don't think most pool stores are trying to give bad results...

As long as the business model is profitable all is well?

It is easier to fool somebody than convince them they have been fooled. Sam Clemens. This is TFPs sisyphean task.

Critical thinking takes practice.

 

[tikoh]

Pool store PH results today was 6.9, my result was ~7.6 with home test kit. Reagent is less than a month old.

Pool store says salt is 3200, same as last test 3 weeks ago before several inches of rain and no added salt. I do not have a home salt test.

My FAS/DPD was 4.5, pool store says 4.3.

The confusion is that it seems their chlorine test is matching mine, PH test is drastically different and salt is obviously wrong unless the copious rain was salty.

Is this the point where I completely distrust their results and go with mine, or go with their computer test?

There are a lot of reasons that the pool store test results are unreliable, but one of them is that pH will actually change in your water sample after you collect it. Dissolved gases can influence pH, so the simple act of shaking or not shaking your sample can affect it. The way they draw the sample can affect it. Lots of variables.