Important findings according how to store open bottles of the reagent for Hanna Marine alkalinity checkers

[EricR]

It's even faster once you get good at it.

Unless, like me, you happen to be color-blind. Ooops

 

[homer1475]

Stop the nonsense and Hanna worship. Just do the Salifert titration, which by the way is just as fast at the Hanna checker method.

So what happens if your color blind and can't see the shift in color?

 

[homer1475]

Unless, like me, you happen to be color-blind. Ooops

We posted at the same time. LOL

 

[Klyle]

Then I suppose the Hanna checkers are the way to go! If your not color blind though, salifert all the way!!!

 

[Big E]

For another data point. This was performed a few days ago back to back---

Last plunger worth in old bottle- 7.6
First plunger in new bottle- 7.5

I never refrigerated the old or new bottle but did a slight flip/shake of the bottle every time I use it.

I also seldom get much more than a .1-.2 difference when I use the Salfert to compare to Hannah.

I test the same time of day and use RO water to clean the vials after testing.

 

[homer1475]

For another data point. This was performed a few days ago back to back---

Last plunger worth in old bottle- 7.6
First plunger in new bottle- 7.5

I never refrigerated the old or new bottle but did a slight flip/shake of the bottle every time I use it.

I also seldom get much more than a .1-.2 difference when I use the Salfert to compare to Hannah.

I test the same time of day and use RO water to clean the vials after testing.

Pretty much my experience with the hanna as well. I always check last batch of reagent to new. Have never seen more then a .3DKH difference between lots.

I have never seen the wild fluctuations some see in threads like this about the hanna in the last 6 years of using one.

Close enough for me, as I do not look to pinpoint a specific number.

 

[Muffin87]

The reagent - let us say 10 degree C.

Do you keep the fridge where you store the reagent at 10°C?
Or you run the fridge colder than 10°C, and take the reagent out of the fridge and let it warm up a bit?

 

[caddnima_reef]

Just to add data here. I am from Seattle. I am on my 4th bottle. And it is always consistent from old bottle to new. Maybe I am lucky? Maybe my weather makes a difference? Or or, that after Evey use, I put the bottle back to the two plastic halves and inside the box that came with it. It says that keep it in dark cool place..... Just sharing.

 

[Lasse]

Do you keep the fridge where you store the reagent at 10°C?
Or you run the fridge colder than 10°C, and take the reagent out of the fridge and let it warm up a bit?

I do not really know which temperature my fridge have in the upper part of the door but if it is 4 degree - my temp when I add 1 ml of this to 10 ml 25 degree C still will be 23.1. For me - its of no concern.

Sincerely Lasse

 

[Reefvision]

I do not really know which temperature my fridge have in the upper part of the door but if it is 4 degree - my temp when I add 1 ml of this to 10 ml 25 degree C still will be 23.1. For me - its of no concern.

Sincerely Lasse

Just to add data here. I am from Seattle. I am on my 4th bottle. And it is always consistent from old bottle to new. Maybe I am lucky? Maybe my weather makes a difference? Or or, that after Evey use, I put the bottle back to the two plastic halves and inside the box that came with it. It says that keep it in dark cool place..... Just sharing.

I have found that my testing results are not different if regeant is refrigerated/not. I put unopened regeant in fridge after reading the initial post . And left the opened regeant that is 4 months old ( maybe older). I test alk about every 2 weeks and when I tested it recently with new regeant just to see if any variation in results , I found none . I am sure that keeping regeant in the fridge can’t hurt though.

 

[piranhaman00]

My theory is people are contaminating their bottles with saltwater or left over reagent in the syringe.

I am currently using a bottle that is 7 months expired and over 10 months old, no issues, matches salifert within the .3 accuracy.

 

[Rmckoy]

Thank you @Lasse
Great information and hopefully will save tons of frustration in the future .

mine will be added to the refrigerator when I get home this evening

 

[Lasse]

I have found that my testing results are not different if regeant is refrigerated/not. I put unopened regeant in fridge after reading the initial post . And left the opened regeant that is 4 months old ( maybe older). I test alk about every 2 weeks and when I tested it recently with new regeant just to see if any variation in results , I found none . I am sure that keeping regeant in the fridge can’t hurt though.

My theory is people are contaminating their bottles with saltwater or left over reagent in the syringe.

I am currently using a bottle that is 7 months expired and over 10 months old, no issues, matches salifert within the .3 accuracy.

I´m do not know if I got some bad batches 1 year ago or/and that Hanna have change anything. I only know that the batches I had get lower and lower result and to keep these batches in my refrigerator helped me to get stable readings even with old reagents. If someone have trust in the quality and do not see any down going result - I´m glad on that persons behave but I will still have my reagent in the refrigerator - it works for me and will for sure not damage the reagent

I do not believe that the statement

My theory is people are contaminating their bottles with saltwater or left over reagent in the syringe.

is totally true - it not true in my case at least

Sincerely Lasse

 

[HuduVudu]

I´m do not know if I got some bad batches 1 year ago or/and that Hanna have change anything. I only know that the batches I had get lower and lower result and to keep these batches in my refrigerator helped me to get stable readings even with old reagents. If someone have trust in the quality and do not see any down going result - I´m glad on that persons behave but I will still have my reagent in the refrigerator - it works for me and will for sure not damage the reagent

I do not believe that the statement


is totally true - it not true in my case at least

Sincerely Lasse

Your findings are still holding true?

 

[Lasse]

Your findings are still holding true?

I still keep the reagent in the refrigerator, still have the same readings between old and new reagents and inline with my Tropic Marine Pro KH test

Sincerely Lasse

 

[HuduVudu]

I still keep the reagent in the refrigerator, still have the same readings between old and new reagents and inline with my Tropic Marine Pro KH test

Sincerely Lasse

Thank you Lasse.

 

[JMetaxas]

The way I solve the uncertainty is to use the Salifert titration kit. I trust it

 

[vahegan]

OK, here I am back to confirm that @Lasse 's method of storing the open reagent works for me.

There was little reagent left in the older bottle which I have been using for a few months now. I have got a surprisingly low reading yesterday (and my readings were consistently dropping in the previous couple of weeks, even though I have increased the doser setting for the 2-part addittive), so I wanted to check and opened a new bottle to compare the results. I got only 0.1KH difference.

With my very first bottle, which I kept at room temperature and was only shaking before each use, I recall that there was a more than KH2 (!) difference when I opened the new bottle.

So, storing the reagent in the fridge works great. Thank you, Lasse, for finding this out for us!

 

[Randy Holmes-Farley]

It is possible that one of the dyes that Hanna uses is susceptible to air oxidation. That would become more and more of an issue as the reagent in the vial declines (more air/O2 to less reagent) and the cooler temps in a fridge could reduce the reaction rate. It might also be very dependent on batch since air oxidations are often catalyzed by trace metals such as iron.

 

[vahegan]

I wonder what dyes they are using that give a significant and consistent change of coloration in a narrow range of pH changes. I am assuming that the method relies on adding enough acid to neutralize the maximum KH in the devices range, then measures the pH to determine the amount of remaining unreacted acid. Meaning, the indicator should give a linear response of coloration in the range from zero and up to acidity required to kill the max KH in the range.