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

[uninformed]

Feed back. Open bottle stored in fridge for1 1/2 month - 7.1 dKH. Newly open bottle - 7.1dKH

Sincerely Lasse

Are they both from the same lot or different lots? That seems like the next question to be answered.

 

[Duncan62]

There is a way to hinder the Hanna alk to show lesser and lesser dKH (or ppm for that matter) with age of open reagent bottle. I had the same story as many have reported here - my reading decrease from a new open bottle with time. Double check with another method show that there was not a real decrease - only that the reagent did not give the colour it should. Comparing with a fresh newly open bottle confirm the false readings of the old reagent. I did a test with shaking the bottle every time I use it - not better result. After this I start to store all open bottles in my refrigerator and voila - it works and give the right readings all the time. I have tested this for 8 months now and comparing with other types of measurements - the last bottle is now 4 months old (open) and still give the same result as my other tests (and a brand new opened bottle)

My findings - Store the open reagent bottle in a refrigerator, shake before use, It works with the cold reagent directly taken from the refrigerator

Other way to handle the test is to always use the same vial, use the same syringe and tip and clean the vale now and then with citric acid

Edit - the period I had tested it - checked my logs - it was 8 months not 6

Sincerely Lasse

Thanks so much.

 

[Lasse]

Are they both from the same lot or different lots? That seems like the next question to be answered.

I did not check that.......... I´ll do next timed

Sincerely Lasse

 

[MorReefs]

Sorry for the necro, but I had this exact issue with my hanna alk checker, where it was testing inconsistent and lower than my other api tests. I changed my reagent for the hanna checker and lo and behold accurate tests again. Wasnt all for naught either as I ended up finding out that my refractometer needed calibrated too.

 

[uninformed]

I just had this exact problem happen with my last two batches of reagent. Both times, the new reagent tested 1.2-1-4 dKH higher than the old reagent. Last time, I chalked it up to a loose connection between the syringe and the tip on the old set. This time, I tested both syringes/tips on the new reagent bottle and was within 0.1.

Into the fridge mine goes. I’ll report back with the next bottle.

One more data point on refrigeration: I have been refrigerating my reagents, open and sealed, at 36°F for exactly the last month. My open bottle was still mostly full (~5 tests used) when I put it in the fridge. This morning, the old bottle and new bottle both tested at 7.8. Both reagents were from the same lot: Lot 9890, Exp. 4/2023.

My next two bottles are from a different lot (Lot 0010, Exp. 5/2023), so that will be an interesting test. I have another tank coming online now, so it may be less than a month before I consume this next bottle.

 

[codenfx]

I've had the same issue with alk testing low. Using the same reagent I had since November last year was now testing at 4.1 dKH which was shocking, tested it at 4.2 and 4.1 the next few days. I decided to purchased a new reagent and tested 7.1 dKH I still don't know if that's accurate so I bought a Salifert kit to check against it and tested at 8.3 dKH I'm so confused which is correct. I am trying the fridge method now to see if it changes anything.

 

[Reef.]

I've had the same issue with alk testing low. Using the same reagent I had since November last year was now testing at 4.1 dKH which was shocking, tested it at 4.2 and 4.1 the next few days. I decided to purchased a new reagent and tested 7.1 dKH I still don't know if that's accurate so I bought a Salifert kit to check against it and tested at 8.3 dKH I'm so confused which is correct. I am trying the fridge method now to see if it changes anything.

What should it be? I would be tempted to trust the Hanna with the new reagent, 6 months for a open bottle of reagent is a long time TBF, is there a recommended use by on the bottle once open? Salifert if very good but more room for error, you also need to stop at the lavender colour not when it turns pink.
Test some fresh salt water, should give you an idea which to trust.

 

[gbroadbridge]

What should it be? I would be tempted to trust the Hanna with the new reagent, 6 months for a open bottle of reagent is a long time TBF, is there a recommended use by on the bottle once open? Salifert if very good but more room for error, you also need to stop at the lavender colour not when it turns pink.
Test some fresh salt water, should give you an idea which to trust.

Hanna say 3 months (6 months max) once opened. I've had new bottles that are out by 0.6dkh compared to a manual HCl titration. I don't use the Hanna Alk checker any more.

 

[codenfx]

What should it be? I would be tempted to trust the Hanna with the new reagent, 6 months for a open bottle of reagent is a long time TBF, is there a recommended use by on the bottle once open? Salifert if very good but more room for error, you also need to stop at the lavender colour not when it turns pink.
Test some fresh salt water, should give you an idea which to trust.

Honestly I'm still not sure what's the correct dKH, my LFS offered to bring in sample and the checker to verify. I did not know it only last couple months which is why I purchased new reagent yesterday exp 11/22 and threw out the old one forgot to look at the exp on that. I'm considering another new reagent to try.

I'll test the Salifert again, I stopped when it turned pink, this time I'll keep an eye on when it turns lavender. Thanks for the tip.

 

[Klyle]

Salifet alk. Haven't used my Hanna in 6 months.

 

[gbroadbridge]

Honestly I'm still not sure what's the correct dKH, my LFS offered to bring in sample and the checker to verify. I did not know it only last couple months which is why I purchased new reagent yesterday exp 11/22 and threw out the old one forgot to look at the exp on that. I'm considering another new reagent to try.

Most folks miss the fact that once open, even if well before the expiry date, you really only have 3 months to use the Hanna reagent. Refrigerating seems to extend the life.

 

[GoVols]

Has anyone else noticed that the fill lines rub off Hanna’s curvets real fast lately?

 

[Klyle]

Has anyone else noticed that the fill lines rub off Hanna’s curvets real fast lately?

Haha yep! I've started cleaning only below the line and it helps. They should sell replacement vials

 

[gbroadbridge]

Haha yep! I've started cleaning only below the line and it helps. They should sell replacement vials

They do sell replacements. I use a Lab pipette to fill the cuvettes as the line is always wrong anyway.

 

[Klyle]

They do sell replacements. I use a Lab pipette to fill the cuvettes as the line is always wrong anyway.

Well shoot

 

[GoVols]

Well shoot

I have used this dosing syringe over the years.

set it pull pull 10mls / it may not be exact, but it will pull the same amount every time that you test.

https://www.walgreens.com/store/c/walgreens-dosage-syringe-with-brush/ID=prod6191613-product

 

[Reef.]

They do sell replacements. I use a Lab pipette to fill the cuvettes as the line is always wrong anyway.

I’ve just bought one too,

I have used this dosing syringe over the years.

set it pull pull 10mls / it may not be exact, but it will pull the same amount every time that you test.

https://www.walgreens.com/store/c/walgreens-dosage-syringe-with-brush/ID=prod6191613-product

if you have some accurate scales, probably need 0.01g or at least 0.1g scales, 10ml of rodi water is 10grams.
I have a similar one, it is near enough spot on.

 

[Klyle]

I have used this dosing syringe over the years.

set it pull pull 10mls / it may not be exact, but it will pull the same amount every time that you test.

https://www.walgreens.com/store/c/walgreens-dosage-syringe-with-brush/ID=prod6191613-product

Ha! Yeah I have the same one, we used it to feed our bearded dragon when she was sick ):

 

[JMetaxas]

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

 

[Klyle]

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

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