Ocean-Like Salinity Levels

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capn7

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Mar 6, 2013
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Phoenix, AZ
Perhaps not, but close. I hope I'm not in a pickle here... Appreciate the review. Just added salt to my pool and it ended up off the charts. I am completely baffled as to how it got this high, and can't help but think there has to be some mistake.

BEFORE: 4/9, 7pm
2.2 FC / 0 CC / 7.6 pH / 80 TA / 70 CYA / 2000 Salt
+12oz Acid (31.45%), +160lb Salt; ran pump 24hrs

AFTER: 4/10, 7pm
7.4 FC (SWG running) / 0 CC / 7.8 pH / 15,600 Salt.
YES, 15,600. 78 drops using the Taylor K-1766 kit.

How is this even possible? Before I started, I tested salt 3x. 4/8 I got 2000ppm twice back to back on the same sample, active water. 4/9 I got the same. This was likely residual from liquid chlorine; just installed the SWG. Added slightly less salt than recommended (added 4 bags @ 40lb, recommended was ~184lbs to get me to 4k). Ran the pool for 24hrs to dissolve and turn. Pool is 10-11k gals. After the crazy high reading, I tested again tonight, 48hrs later, and stopped after 40 drops (8000 ppm) because I didn't want to keep dropping up to 76 drops and exhaust my entire bottle of Silver Nitrate. The amount of salt recommendation was consistent between PoolCalc, SWG manual, and the back of the salt bags.

SWG is now off (it did run for 8hrs that next day, 12hrs after salt was added).

Any clues as to what I am missing here? Did someone hop the fence and generously dump another 25 bags of salt into my pool? I don't see how I could possibly go from 2000 to 15,600 ppm using 4 bags of salt...
 
Well, I doubt you are that far off on your pool volume so you certainly only changed the salt level by about 1750ppm between the two tests.

That means one of the tests is wrong. If your water had previously been at close to 14,000ppm, you would have been able to taste the salt and would have seen salt residue on the deck when water dried.

So I think your current test has an issue. Maybe dilute a sample of pool water 5 to 1 and test or take a sample to a pool store for a reference check. Did you add anything to the pool besides the salt?
 
I think it is obvious that the salt is not really at 15,600, so either your are doing the test wrong or something is wrong with your test kit.

My suggestion would be to turn the SWG back on and see what it says the salt level is. I'm not familiar with that particular SWG, but I find it is much easier to just make the SWG happy.

In my case, I've never been able to make my test kit come within 800 ppm of what my SWGs say..

Jim R.
 
JohnT said:
Well, I doubt you are that far off on your pool volume so you certainly only changed the salt level by about 1750ppm between the two tests.

That means one of the tests is wrong. If your water had previously been at close to 14,000ppm, you would have been able to taste the salt and would have seen salt residue on the deck when water dried.

So I think your current test has an issue. Maybe dilute a sample of pool water 5 to 1 and test or take a sample to a pool store for a reference check. Did you add anything to the pool besides the salt?
Click to expand...
The only other thing I added was a bit of acid. Just tested a 1:4 dilution at 3600.

Sent from my SAMSUNG-SM-G900A using Tapatalk
 
What is the reagent number on the silver nitrate bottle - R-0718 or R-0706 ?

What water sample size are you using ?
 
Sample size is 10mL not 25mL. That's why your drop count is so high. You have roughly 2.5 times the number of Cl- ions to titrate...retest with a 10mL water sample.
 

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capn7 said:
Well that was embarrassing. Thanks for catching my goof. Apparently in a 24hr period I had already forgotten the sample size. Now reading at 6200.
Click to expand...

Happens to everyone. I once tried titrating my chlorine test using the R-0013 CYA reagent...wasted 1/4 of a bottle of CYA reagent before realizing my mistake. Doh!!

Still, even at 6200ppm, something is not right. You're much higher than your 4 bags of pool salt would imply. I'm guessing your initial salt concentration was a lot higher than you tested it to be.
 
If your initial test was done with a 25mm sample, correcting for the 2.5 error is 5000ppm. At that level the K1766 can be up to 10% out (mine was) which puts you at 4500ppm. From PoolMath adding 156lb of salt will put you at 6200ppm. The extra 4lb is well within the variance.
 
AUSpool said:
If your initial test was done with a 25mm sample, correcting for the 2.5 error is 5000ppm. At that level the K1766 can be up to 10% out (mine was) which puts you at 4500ppm. From PoolMath adding 156lb of salt will put you at 6200ppm. The extra 4lb is well within the variance.
Click to expand...
:scratch: I am not sure this is right. If they used 25ml for the first test and added 10 drops (thinking 200ppm each), then the 2000ppm reported would be 2.5 times too low, not too high.

Wondering if only using 1 drop of the first reagent in the 25ml could have been causing a problem too.
 
jblizzle said:
Wondering if only using 1 drop of the first reagent in the 25ml could have been causing a problem too.
Click to expand...

It shouldn't matter. The potassium chromate is merely an indicator. Once the last little bit of chloride reacts with the silver to form the last bit of Silver chloride precipitate, the next silver ion will immediately react with the chromate ion to develop a brick red color. The only issue one might have is the silver chromate will be a little diluted so the brick red won't be that intense.

I also agree, if the original 2000ppm were measured with a 25mL sample, then the real original chloride level is lower, not higher. But the numbers are still off somehow...
 
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