Taylor K-1766 inaccuracy

[JerseyMike37]

I recently converted my pool to salt water and initially added a bit too much salt (salinity around 4000)
I bought the accuchek strips and confirmed it. Then I bought the Taylor K-1766 and that also confirmed 4000.

I replaced around 10% of the water and rechecked...got 3800 on the AquaCheck and 4000 on the taylor

then I replaced another 10% and rechecked....3600 on the aqua check and 4000 on the taylor

I then replaced another 10% and rechecked....3400 on aqua check and 4000 still on the Taylor.


I am adding the drops one by one and have the Taylor magnet stirrer.....it starts changing to salmon around 3400 but goes right back to milky....then at the 20th drop it changes for good to a brick color so I figure 4000ppm...I know that the strips are supposed to be less accurate but given the water changes I can't help but think that the strips are more accurate.

the salt generator is about 200-400 higher than the strips but did change with them, pool store is a touch lower around 100 less than strips.

does anyone else have this issue with the Taylor k-1766?

 

[PoolStored]

What is the date on the reagent?

 

[JerseyMike37]

good point, I will check when I get home, I did buy it from amazon and they often have older stock there

 

[duckcmmndr]

I have that kit and it is easy to go past the proper endpoint. Instructions say "until color changes from yellow to a milky salmon (brick red)" So we are looking for the time at which is changes and not looking for a solid brown color, you can mix one drop of the indicator with 1 drop of the reagent to see the color you are shooting for.

You have to also keep in mind that with a 10ml sample size your accuracy is 200ppm and also if your 10ml sample is not exactly the same every time (i.e. read from the Top/Middle/Bottom of the meniscus) your results will vary. I recommend the Taylor sample sizer to get "repeatable" measurements.

I have not done it..but I have read that you can use a 25ml sample and then each drop of R-0718 Silver Nitrate Reagent is 80ppm salt so now you are a little more accurate. The math works out (10 / 25) * 200 = 80, so I am going to assume that is correct.

 

[JerseyMike37]

I have that kit and it is easy to go past the proper endpoint. Instructions say "until color changes from yellow to a milky salmon (brick red)" So we are looking for the time at which is changes and not looking for a solid brown color, you can mix one drop of the indicator with 1 drop of the reagent to see the color you are shooting for.

You have to also keep in mind that with a 10ml sample size your accuracy is 200ppm and also if your 10ml sample is not exactly the same every time (i.e. read from the Top/Middle/Bottom of the meniscus) your results will vary. I recommend the Taylor sample sizer to get "repeatable" measurements.

I have not done it..but I have read that you can use a 25ml sample and then each drop of R-0718 Silver Nitrate Reagent is 80ppm salt so now you are a little more accurate. The math works out (10 / 25) * 200 = 80, so I am going to assume that is correct.

thanks, that is just what I was wondering....so maybe I'm reading it wrong and it is really when the color first changes to salmon (and then changes back).
I do always try to read the bottom of the meniscus (I was a chemist undergrad) but might consider the Tayler sample sizer.

 

[jets521]

Is this the consensus?

You stop counting drops at the first flash of the milky salmon color? Even if upon swirling it changes back to milky? And NOT waiting until it permanently changed to milky salmon?

 

[PoolStored]

You stop counting drops at the first flash of the milky salmon color? Even if upon swirling it changes back to milky? And NOT waiting until it permanently changed to milky salmon?

No, when it permanently changes. Smart Stir really helps with this...

This: First change (that holds) from yellow to a milky salmon (brick red) is the endpoint.

From this: Salt Test

 

[PoolStored]

I have not done it..but I have read that you can use a 25ml sample and then each drop of R-0718 Silver Nitrate Reagent is 80ppm salt so now you are a little more accurate. The math works out (10 / 25) * 200 = 80, so I am going to assume that is correct.

Yes, this is correct.

 

[jets521]

Great, thanks for clarifying

 

[Katygreys]

Slightly off topic…I haveread dozens of times how Amazon can have old/expired/near-expiration reagents. I have no doubt this is true. Just wanted to get a positive perspective on the record: In the past 6 months I’ve ordered a K2005, K2006C, and a few reagent refills. All were fresh with no issue at all.

(I’m sure my next order will now have expiration date of 1988 )

 

[flynwill]

I have had good results ordering from Amazon as well. The reagents are often not "factory fresh", as I think most have 2 years of dating when they leave taylor, but I have never gotten less than a year and have no worries about using them up before they expire.