Which test results to believe?

lacandelaria

Gold Supporter
Aug 13, 2023
9
Scottsdale, AZ
Pool Size
50000
Surface
Plaster
Chlorine
Liquid Chlorine
Greetings everyone. I just joined TFP and would appreciate your advice on pool testing. I bought a Taylor K-2006 test kit and performed all the recommended pool chemical tests several days in a row. I also took the same water sample I used for my tests to the local Leslie's Pool store and had them perform their test. The greatest difference between my Taylor test results and the Leslie's test results was in the alkalinity readings. My readings were 140 ppm, 160 ppm, and 150 ppm total alkalinity. The Leslie's test results were 75 from one store and 76 from another store. If my readings are correct, then I need to lower alkalinity, but if Leslie's are correct, then I need to raise it. You can see my conundrum. I am known to be a perfectionist and followed the testing videos on the Taylor website exactly, so I have some level of confidence in the readings I took given the good reputation of the Taylor test kit. Any advice? Thank you.
 
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You can see my conundrum
No, i cannot.

You bought a reliable test kit. Use it exclusively. Getting second opinions is a fools errand and the only thing they will do is make you question your reliable readings.

Would you ever cheat off the dumbest kid in class when you had an A+ average ? Of course not. Who cares he got 3 right last time ? He's going to get more wrong than right THIS time. Stick with your gut (k2006) and you'll do just fine.

That all said, they use a different TA value that's adjusted for the CYA. It only matters for CSI calculating and PoolMath calculates it for you. Using adjusted TA to dose from is rumored to be another scam of thr pool store as an easy way to start you on the roller coaster to keep you coming back again and again.

Ahem. Excuse my terrible manners. Welcome to TFP !!!!


Pool Care Basics
FC/CYA Levels
 
Welcome to TFP! :wave:

Believe your results. Pool store results are inaccurate. Also, the PS result is probably 'adjusted' alkalinity - which we don't use.

Post a full set of current test results.
FC
CC
pH
TA
CH
CYA Water temperature

Or use PoolMath and set the app up to share results to your forum account.

Extended test kit directions - Extended Test Kit Directions Archives
TFP TV - TFP-TV

With our hard water (high CH levels) in the PHX area, a TA in the 50-70 range will work well.

Suggest you read thru Pool Care Basics
 
Trust your results!
& Let’s see them 👀 all.
As mentioned “they” use “adjusted” alkalinity so “they” can sell you expensive baking soda.
Btw - that’s a huge pool!
 
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This site is odd sometimes. The 17-year-old kid watched their half hour video in the breakroom to become a certified Leslie's professional. Thats almost as good as a pHD in my book.
 
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Always trust your own testing. The more you test the better you become.
Test your tap water as well - good to have as a base line for what you add to your pool due to evaporation.
 
No, i cannot.

You bought a reliable test kit. Use it exclusively. Getting second opinions is a fools errand and the only thing they will do is make you question your reliable readings.

Would you ever cheat off the dumbest kid in class when you had an A+ average ? Of course not. Who cares he got 3 right last time ? He's going to get more wrong than right THIS time. Stick with your gut (k2006) and you'll do just fine.

That all said, they use a different TA value that's adjusted for the CYA. It only matters for CSI calculating and PoolMath calculates it for you. Using adjusted TA to dose from is rumored to be another scam of thr pool store as an easy way to start you on the roller coaster to keep you coming back again and again.

Ahem. Excuse my terrible manners. Welcome to TFP !!!!


Pool Care Basics
FC/CYA Levels
Cheating off the dumbest kid--too funny! Thank you for putting things in perspective.
 
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Thank you everyone for taking the time to reply to my question and helping me get started on my pool care journey. I have spent hours reading various blogs, watching videos, and taking training courses (Swim University, Swimming Pool Steve, TFP), but I have often found the comments and experiences of users most invaluable. For those who asked, here are my other chemical readings:
pH: 8.0
FC: 5.2 ppm
CC: 0.2
Calcium: 840 ppm
CYA: 140 ppm
 
If by dilution you mean the Taylor CYA test, then yes, I used the diluted method. Frankly, the CYA is so great that the liquid level no longer registers in the numbers, it hits at the CYA lettering on the testing vial. At this point, I am deferring to the test readings I got from the dumbest kid. I have been told in the past by our various pool cleaning people that we have high CYA and need to drain and acid wash our pool. Given how precious water is in our area, I think it would be practically criminal to empty a 50,000 gallon pool, not to mention that from all I have read, now is not a good time to drain a pool given the 115 degree days. I suppose I could drain and fill incrementally, but given the amount of evaporation we experience, I am going to try applying patience and switch to liquid chlorine with the hope that over time this will reduce the CYA. I also purchased the GreenStory Cyanuric Acid Remover. Sigh...probably marks me as a sucker given the mixed reviews of this product, but I thought it was worth a try. I did check into RO, but it was exorbitantly expensive for this amount of water.
 

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I think it would be practically criminal to empty a 50,000 gallon pool
Water cones from the earth, and is returned to the earth. It's never 'wasted'. The most someone could argue is that it gets relocated a bit.

They'll build 5 new golf courses tomorrow, and a dozen hotels with pools and 200 rooms sucking water, but they've made you feel guilty about it. :roll:
not to mention that from all I have read, now is not a good time to drain a pool given the 115 degree days.
See the no drain exchange part :
 
You would want the no drain exchange because you want to protect your plaster in this heat. And with such a large volume, it is multiple days to fill. The no drain exchange is not as efficient but better than that chemical CYA remover.

While CYA can decrease over time it is a very slow process so the no drain exchange is the best solution.

Also, there is no need to do an acid wash - not sure why that was recommended as that can damage plaster.
 
You need to do the diluted cya test
step 8
👇
If your cya is truly 140 you don’t have to drain/exchange the entire pool volume.
More like 50-60% to get to a reasonable level. This will also lower your ch by 50-60% which is needed.
Take the cya reducer back & get your money back.
You need to do the no drain exchange as recommended & linked above.
Replacing water lost to evaporation does not reduce your cya or ch level.
 
You need to do the diluted cya test
step 8
👇
If your cya is truly 140 you don’t have to drain/exchange the entire pool volume.
More like 50-60% to get to a reasonable level. This will also lower your ch by 50-60% which is needed.
Take the cya reducer back & get your money back.
You need to do the no drain exchange as recommended & linked above.
Replacing water lost to evaporation does not reduce your cya or ch level.
Thank you for the link to the diluted CYA test. My results put my CYA in the 140 - 150 range.
 
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Welcome to TFP! :wave:

Believe your results. Pool store results are inaccurate. Also, the PS result is probably 'adjusted' alkalinity - which we don't use.

Post a full set of current test results.
FC
CC
pH
TA
CH
CYA Water temperature

Or use PoolMath and set the app up to share results to your forum account.

Extended test kit directions - Extended Test Kit Directions Archives
TFP TV - TFP-TV

With our hard water (high CH levels) in the PHX area, a TA in the 50-70 range will work well.

Suggest you read thru Pool Care Basics
As a fellow Arizonan, does our harder water concern you as far as your pool is concerned? Do we just live with it or attempt some correction? I have softened water in the house and was wondering whether I could just run a hose from the nearest faucet out to the pool to add some softened water. Just spit-balling here--probably not very practical.
 
CYA: 140 - 150 ppm

If your CYA is 140 or higher and CH is 840, a full drain this Fall will be warranted (it's too hot to do it now).

Your FC of 5.2 is about one half of the minimum required for a CYA of 140.
Be aware, the pH test will read falsely high with FC > 10.

You may be able to limp along until mid/late September and the temps cool. But you will have to be diligent with FC and pH. As mentioned, your other option is a no drain water exchange - butchances are to get a 50%-60% reduction in CYA, you will need to exchange close to 75% or more of your pool volume.
 
You need to do the diluted cya test
step 8
👇
If your cya is truly 140 you don’t have to drain/exchange the entire pool volume.
More like 50-60% to get to a reasonable level. This will also lower your ch by 50-60% which is needed.
Take the cya reducer back & get your money back.
You need to do the no drain exchange as recommended & linked above.
Replacing water lost to evaporation does not reduce your cya or ch level.
I am assuming the reason you say that replacing water lost to evaporation will not reduce the CYA is because the CYA will not evaporate but will simply concentrate in the water that remains? Ergo, the need to drain/exchange. If so, makes sense.
 
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As a fellow Arizonan, does our harder water concern you as far as your pool is concerned? Do we just live with it or attempt some correction? I have softened water in the house and was wondering whether I could just run a hose from the nearest faucet out to the pool to add some softened water. Just spit-balling here--probably not very practical.
One you get your CH to an acceptible level, using softened water for your autofill would be great. Not so much for a water exchange or full refill though. Based on the size of your softener and the softener settings, you will only get 1000-4000 gallons of soft water from one regen cycle.

I plumbed my softener to my autofill about 2 years ago. In that time, my CH has risen 50ppm - instead of over 250ppm per year (or more) with unsoftened water.
Was it a pain to run the PVC pipes? Yes
Would I do it again? Without hesitation

Between the soft water for the autofill and adding a SWG, my pool is very easy to take care of.
 
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I am assuming the reason you say that replacing water lost to evaporation will not reduce the CYA is because the CYA will not evaporate but will simply concentrate in the water that remains? Ergo, the need to drain/exchange. If so, makes sense.
CYA, CH, salt and a few other items will remain in the pool unless the pool water is removed thru splashout or draining. Those items remain even though water evaporates and you add more water. And since our water is hard, the calcium (CH) levels continue to climb.

CYA will degrade s-l-o-w-l-y. You may lose 5-10 ppm monthly in summer. With a CYA of 140-ish, waiting for it to degrade an appreciable amount won't work for you.

My 12,000 gallon pool evaporates between 1 and 1.5 times each year. Chances are your large 50,000 gallon pool evaporates around 20,0000 gallons yearly - maybe more.
 
CYA will not evaporate but will simply concentrate in the water that remains? Ergo, the need to drain/exchange.
Correct. On the east coast and parts of the Midwest, we tend to drain VS fill, from the abundance of rain. Mixed water with CYA comes out, and 0 CYA fill water goes back in, leading to a loss.

For you, 0 CYA evaporated water leaves and 0 CYA fill water is added, so no change occurs.
 
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