Such a difference in test results from pool store?

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nehsmit

nehsmit

0
Nov 8, 2016
40
Bridgewater, NJ
I have the Taylor 2006 and a new 30000 IG Plaster pool. I posted test results yesterday. I tested again today and then went to the LPS to have them test. They used a Bioguard water analysis. Same water sample. Only difference was drive time to the pool store and testing time. Here are the results. What do you make of this?

Test Taylor LPS
FC 2.5 0.4
CC 0.5
TC 0.4
pH 7.6 6.6
Alk 110 0
CH 130 76
CYA 0 8

They said i had copper in my water. They asked me to add Pool Magnet Plus 2qts.

Also added 36lbs of Balance Pak 100.

Thoughts are appreciated. Thanks in advance.
 
tim5055 said:
We don't trust pool store numbers at all.

Did you actually add what they suggested??
Click to expand...

Ashamed to say yes. I was so freaked out that maybe my testing was off. Couldn't believe how it could be so different. I would understand a small difference but these numbers are so far off. How do we explain such a difference? I know we dont trust pool stores but doesn't this seem so far off?
 
When you test you are sure your vials are clean, your equipment is not contaminated from other pools water, and you are repeatedly doing the same tests with the same process. So your testing is always more accurate. It is best to just not confuse yourself and take samples to pool stores. You then add stuff (do you know exactly what those two products are meant to do?). You just had the pool built, new water. How did you get copper in the water? You have to add it, normally not present in fill water.

Do a complete set of tests, use Pool Math and Pool School to come up with what you think needs to be added for one time treatments and ongoing maintenance, and post it all for the forum to provide feedback.

Thanks for posting.
 
nehsmit said:
How do we explain such a difference?
Click to expand...

The goals of pool store testing are likely to be: assembly line speed and profit margin support (lowest testing cost, maximum legal product suggestion allowance).

Notice how their goals are not likely to be: accuracy

They don't offer any guarantee that they are within a certain % to the actual value, do they? They don't brag about how they use the best reagents or even promise to follow the instructions.

Here are some quotes:

JoyfulNoise said:
The "precision" of the test is 1 drop, that's all you have control over.

The "accuracy" of the test is how close it comes to measuring the real value of FC. This is a function of the reagent chemistry. This can only be tested in a lab using a known chlorine standard. This is something Taylor would do as part of any standard statistical control process when manufacturing reagents.

The "tolerance" or "repeatability" of the test is a statistical measurement on the person doing the test and the equipment used (dropper bottles, humans hands and eyeballs) - if the same person performs the test 100 times on the same batch of water, do they get the same value every time or do they get ten different values, or 20 different values, what's the spread and standard deviation of all the measurements, etc, etc.
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Does the Pool Store Tester execute the testing with the same care and attention to detail as you do? Do they drop the drops no faster than 1 per second, mixing well between? Do they follow the instructions as good as you do? Do they use sunlight for the CYA test? Pool Store Testing, even if using your test kit, is susceptible to tolerance/repeatability errors far worse than your own testing, wouldn't you agree?

duraleigh said:
The FAS/DPD test is at the heart of what we teach and I find it deadly accurate. There are many variables that produce that test result....circulation, taking a good sample, keeping your equipment clean, but at the center is always the operator. This is a good time to review the pre-testing advice found in the TF-100.


1. Keep your chemistry clean and dry (especially the R-870 powder)
2. Keep your Test Kit out of the Sun, heat and rain
3. Measure everything carefully
4. Rinse your equipment before and after each test
5. Reseal all chemistry tightly
6. Collect all your pool water samples about a foot under the surface.

Careless measuring, handling or​
testing procedures will usually result in inaccurate results.​
​
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Did you catch that? "but at the center is always the operator" and even though I LOVE LOVE LOVE my pool store for selling me super fresh and super cheap trade bleach, their operators are rubbish for water testing. They do it dozens of times each day, and hundreds on weekends and before holidays. They have a line of people waiting. They get paid minimum wage. They don't like their jobs. They don't care about your pool. They think you're an idiot if you let them test it and sell you $200 worth of trash you don't need. "Careless measuring" is the only way they do it. Did their CYA sample take 7mL or was it 7.7mL? That's a 10% difference! Do they even know what a meniscus is? Do they care? Did they rinse everything before and after? Is it clean? You get the idea.
 
nehsmit said:
I have the Taylor 2006 and a new 30000 IG Plaster pool. I posted test results yesterday. I tested again today and then went to the LPS to have them test. They used a Bioguard water analysis. Same water sample. Only difference was drive time to the pool store and testing time. Here are the results. What do you make of this?

Test Taylor LPS
FC 2.5 0.4
CC 0.5
TC 0.4
pH 7.6 6.6
Alk 110 0
CH 130 76
CYA 0 8

They said i had copper in my water. They asked me to add Pool Magnet Plus 2qts.

Also added 36lbs of Balance Pak 100.

Thoughts are appreciated. Thanks in advance.
Click to expand...

That 'Balance Pak 100' is nothing but way overpriced baking soda, and 36 lbs of it just added 70ppm to your TA, making it 180ppm now.......

As mentioned, trust your own testing.

https://www.troublefreepool.com/thr...results-are-in-Pool-Store-Tests-are-different

https://www.troublefreepool.com/threads/11890-TF100-vs-pool-store-test-getting-different-results

https://www.troublefreepool.com/thr...test-results-so-different-than-the-pool-store

http://www.troublefreepool.com/threads/73153-My-Tests-vs-Pool-Store-Tests-(Huge-Difference-in-CYA)
 
Anytime you get a 0 for TA be very suspicious of the results. If this was a computer analysis system odds are it will be wrong. Computerized systems need frequent re-calibration for any hope of accuracy.
 
zea3 said:
Anytime you get a 0 for TA be very suspicious of the results. If this was a computer analysis system odds are it will be wrong. Computerized systems need frequent re-calibration for any hope of accuracy.
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That's what I'm thinking. It was a computerized test for everything. Injected small sample into a cartridge and let the computer do everything. No tests done by hand.
 
Well, at least you learned your lesson with something that is not the end of the world. Assuming your TA is now high, it will just mean your pH will rise a little quicker than it might have normally.

Always trust your testing.

Do not take them a water sample until you are extremely comfortable with your testing, and only then can you do it for amusement to,see what they try to sell you.
 
Search for a post on pool stores suggesting Jack's magic yellow to a clorine pool. They are suggesting adding bromine to a clorine pool. That pretty much tells you of pool stores.

Pick up a gallon of ma to undo what they sold you, adding and testing correctly of course!
 

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I know I had seen a post on what specific things to buy (even mentioned brands if I remember correctly) to adjust all the parameters. For us Noobs, anyone know where that thread is? Looking specifically for:
pH to increase or decrease use....
Alk to increase or decrease use...
Calcium....
Etc, etc, etc. Thank you all again for all the help and eduction.
 
What do I need to add SPECIFICALLY. NOOB Here

Hi all,

I am a NOOB and just learning the TFP way of thinking. I have a 30,000g IG plaster pool open less than 1 week. Here are my test results from today using a Taylor 2006 kit. Ive done pool math but my question is what order and specifically which muriatic acid and which calcium chloride and which stabilizer do I use? Where do I get them from and what order do I add them? All at once? One at a time? wait how long in between each addition? I live in Central NJ.

Sorry for the noob questions.

FC/CC 0/0
ph >8
alk 190
CH 170
CYA 0

Thanks in advance.
 
Re: What do I need to add SPECIFICALLY. NOOB Here

Im thinking I can just walk into my local Home depot or walmart and get the products. Are these products appropriate? More concerned about the calcium and the stabilizer.

Muriatic acid - HDX 2x1-Gallon Muriatic Acid-2118 HD - The Home Depot

Stabilizer - Pool Time 5 lb. Chlorine Stabilizer-23417PTM - The Home Depot

Calcium chloride - Vaporizer 9 lb. Calcium Pellet Ice Melt Jug-VP-CP09JG - The Home Depot

Bleach - HDX 121 oz. Germicidal Bleach-23008948211 - The Home Depot
 

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