My recollection is that the failures of stability were noted early after the release of the test, and possibly they redid the formula shortly after. As they have with multiple other recently released tests. Ammonia & Mg for example.
checkable idea at least. Just have to get a couple of the people who most clearly noted instability to give a new bottle another shot over a few months.
With the Hanna tester I use glass vials to store the reagent, and the first thing I do is remove the floaters with the syringe. I have not seen any notable change in chemical accuracy when the reagent initially contained floaters.
I do the same. I swirll all reagents around just a bit prior to use. Nobody ever told me to do that, I guess I just do it for piece of mind that nothing is settled on the bottom.
This is a follow-up to my post regarding my solution to the apparent drift over time of the Hanna Alkalinity Test. I believe I witnessed the drift years ago, and began using small 10ml glass vials to store the reagent. With that change the drift seemingly disappeared.
In an attempt to recreate the drift, I performed a full reagent bottle of tests (24) over the last three months, and compared the results of the reagent stored in the Hanna bottle to the results from reagent stored in my 10ml glass vials. Both methods used reagent from Lot 1293, and a commercial alkalinity standard was used at the beginning and end of the test for calibration and verification.
The number of days into the test, test date, alkalinity of each test, and difference was recorded. The difference between the tests verses time was plotted. The test ran until the reagents were consumed.
At no point during the test was there any significant difference between the two test methods. All of the tests tracked within 0.1 dKH of each other. Verification of both tests to the alkalinity standard at the end of the test revealed that neither reagent drifted.
The cause of the apparent drift remains a mystery.
Thanks for the confirmation!This is a follow-up to my post regarding my solution to the apparent drift over time of the Hanna Alkalinity Test. I believe I witnessed the drift years ago, and began using small 10ml glass vials to store the reagent. With that change the drift seemingly disappeared.
In an attempt to recreate the drift, I performed a full reagent bottle of tests (24) over the last three months, and compared the results of the reagent stored in the Hanna bottle to the results from reagent stored in my 10ml glass vials. Both methods used reagent from Lot 1293, and a commercial alkalinity standard was used at the beginning and end of the test for calibration and verification.
The number of days into the test, test date, alkalinity of each test, and difference was recorded. The difference between the tests verses time was plotted. The test ran until the reagents were consumed.
At no point during the test was there any significant difference between the two test methods. All of the tests tracked within 0.1 dKH of each other. Verification of both tests to the alkalinity standard at the end of the test revealed that neither reagent drifted.
The cause of the apparent drift remains a mystery.
Confirmation...since i no longer remove the seal cap and use a syringe with a needle to take the 1ml.
i have the impression that it is more stable...
the shift seems smaller. (Gap between old and new bottle)
No refrigeration ...
but i didn't document it...
Ditto. I also started doing this per the original poster. I just opened a new bottle of reagents and it precisely matched the bottle I just emptied. Awesome tip
