Weird Taylor K-1766 salt test results

[ManiacalMama]

So I'll be converting to salt soon and ordered the Taylor K-1766 salt test. This morning I tested the water twice. First time was 15 drops (3000ppm) and second time was 16 drops (3200).
This is not yet a salt pool. I've never added salt. Is it really possible to have that much salt in it just from chlorine? The pool was re-plastered 2 years ago, so this is only 2 years worth of liquid chlorine.
The water temp is only about 58 degrees. Should I try again after letting the water come up to room temp or does that even matter?
What say you?
Thanks!

 

[Newdude]

This is not yet a salt pool. I've never added salt. Is it really possible to have that much salt in it just from chlorine?

Sure is. And it dispels any and all myths that fly about the ‘salt pools’ being so bad for equipment and hard scapes.

Also worth noting, the K-1766 being the most accurate test available has a tolerance of +\- 200. If the true level is 3k, 2800-3200 is considered accurate.

Once you are up and running, the cell will either produce or not. It doesn’t do better at a certain amount providing you aren’t high. It is not as accurate as the K-1766 but sadly you can’t reason with it. So if it’s happy, you’re happy.

 

[Rocket J Squirrel]

Not likely. Did you use the correct sample size? Notice that the instructions say to fill the 25ml test tube only to the 10ml line.

 

[Newdude]

Notice that the instructions say to fill the 25ml test tube only to the 10ml line.

+1. This part got me many times. The brain just shut off at the fill the 25ml sample tube part……….. to 10 ml.

So I’d like to amend my answer that it’s still possible but confirmation is needed. One member recently was at ‘salt level’ and another was over it with only LC and MA. I believe they both had more time to get there, but still.

 

[ManiacalMama]

Not likely. Did you use the correct sample size? Notice that the instructions say to fill the 25ml test tube only to the 10ml line.

Luckily I did notice it and used the correct 10ml sample size for both tests. Had I accidently used 25ml, I suspect the test would have given me a lower result and I probably wouldn't have questioned it

Just for shoots and giggles I'm going to let my sample come to room temp and see what happens. I can't seem to find any mention about temp for test, only for SWG operation.

 

[ManiacalMama]

+1. This part got me many times. The brain just shut off at the fill the 25ml sample tube part……….. to 10 ml.

So I’d like to amend my answer that it’s still possible but confirmation is needed. One member recently was at ‘salt level’ and another was over it with only LC and MA. I believe they both had more time to get there, but still.

Well that will be cool if I end up not needing to add any at all, just for the convenience of not having to lug the bags out to the pool. Although I probably won't be actually running the SWG until spring.

 

[borjis]

The cya test is definitely effected by temp.
70 degrees or above recommended.
Not sure for salt. Worth a try.

 

[ManiacalMama]

Does MA add salt too?

 

[ManiacalMama]

The cya test is definitely effected by temp.
70 degrees or above recommended.
Not sure for salt. Worth a try.

I am aware about the CYA test...I usually have to warm the water a little in the spring.

 

[JamesW]

Yes…it’s cold…VERY COLD…especially out here on the East Coast.

Record low temps, blizzards, and runs on the grocery store for bread, milk, and toilet paper (inside joke for us in the Baltimore area) make this such a “special” time of the year.

Brrrrrrr… As a result, this frigid weather has led to a barrage of calls and e-mails about testing pool/spa water with low temps. Imagine that! Seriously though, low temps can affect test results, reaction times, solubility within the sample, and reagent efficacy.

For example, it may take a few more drops of reagent in a total alkalinity or calcium hardness drop test before you see the color change, which will result in a false-high reading.

In a pH test, some reagent components may precipitate when the reagent is added to a low-temp sample, causing faded test colors, inaccurate results, and/or no reactions at all!

It’s also widely known that CYA testing of low-temp water will provide false-low test results (even at water temperatures in the 60s) because the speed in which the precipitate forms is slowed down tremendously.

Other tests could be affected as well.

For test strip users, be aware that temperatures <45°F (7.2°C) can affect color development.

And for those of you who use meters, you’ll be happy to know that low-temperature samples do not usually affect test results, but it would be wise to verify this by checking your meter’s specifications.

As a general guideline, we recommend not testing pool/spa water samples that are <45°F (7.2°C).

Another important reminder: Store reagents and test kits in a temperature range of 36°F–85°F (2.2°C–29°C).

So, what’s the “get around”? If you must test pool/spa water <45°F (7.2°C), collect the sample from 18″ below the surface (again…brrrrrrr!) in an opaque container, bring it inside to a warmer environment, and wait a few minutes before performing the test. Remember…patience is a virtue!

How Cold Temperatures Affect Your Pool/Spa Water

 

[JamesW]

Do pool or spa water samples have to be at "room temperature" before testing begins?

For consistency, reliability, and accuracy, we recommend sample temperatures to be between 50-90℉. Sample temperatures <50℉ or >90℉ may produce unexpected color development.

Questions In Our Pool/Spa Mailbag

 

[JamesW]

Does MA add salt too?

Yes.

 

[ManiacalMama]

Questions In Our Pool/Spa Mailbag

Well the pool water is at about 58 degrees, and the sample sat on my kitchen counter for a little while before I ran my tests, so it was probably close to 60 degrees by then. But I'm gonna let it sit there all afternoon and test again. I'll let you guys know if I get a different result, but I'm thinking maybe it's just that high. We'll see!

 

[Newdude]

 

[JamesW]

1 gallon of acid adds 4.87 lb of salt.

Every gallon of 12.5% sodium hypochlorite adds 1.7 lbs of salt.

So, acid actually adds about 2.86 times more salt per gallon than even liquid chlorine.

How many total gallons of acid and liquid chlorine have been added since the pool was filled?

 

[JamesW]

Assuming 2.65 ppm chlorine demand per day for two years, that's 1,945 total ppm, which would be 210 gallons of 12.5% liquid chlorine, which would provide 3,200 ppm.

 

[ManiacalMama]

1 gallon of acid adds 4.87 lb of salt.

Every gallon of 12.5% sodium hypochlorite adds 1.7 lbs of salt.

So, acid actually adds about 2.86 times more salt per gallon than even liquid chlorine.

How many total gallons of acid and liquid chlorine have been added since the pool was filled?

A lot?
That is about as accurate as I can get.
Acid - a lot at startup, and then since then I probably average 1 qt. a week, sometimes a little more.
LC - That obviously varies depending on time of year...Anywhere from 1+ quarts a day to 1 per week.
I'm an eyeballer, I stopped measuring and keeping track a long time ago. I realized that if I was too rigid about it I would never do it. LOL

Edit to add: I use 31% MA and 10% LC

 

[Rocket J Squirrel]

Luckily I did notice it and used the correct 10ml sample size for both tests. Had I accidently used 25ml, I suspect the test would have given me a lower result and I probably wouldn't have questioned it

Good for you for doing it right. But a larger sample of the same salinity would require more drops for the target color change, yielding a false high result.

 

[ManiacalMama]

Assuming 2.65 ppm chlorine demand per day for two years, that's 1,945 total ppm, which would be 210 gallons of 12.5% liquid chlorine, which would provide 3,200 ppm.

There are times in the summer I can burn up even 3+ ppm in a day, but only when the cover isn't on it. The pool is currently uncovered now and loosing less than 1ppm a day. Like I said, it varies. That's not to say that I don't test my pool, but I've gotten a feel for it's appetite.

 

[ManiacalMama]

Good for you for doing it right. But a larger sample of the same salinity would require more drops for the target color change, yielding a false high result.

lol I figured that out after I said it
But I definitely did the 10ml