Hanna checker ALK

[Joedubyk]

I love my hanna but after I finished up I opened up another bottle of reagent (same batch and lot) and it tested 1 full dkH lower than the previous bottle. I was getting 8.2 , EVERy day for the past week or so.

Now, I test and it's 7.2

Only two things are possible

a) the last 5-6 tests of the bottle were bad readings
b) the new bottle is 1 dkh incorrect

It's not the biggest deal in the world if I lost 1dkh over a few days, but it is when I want accurate readings I can trust.

And please save all the "DiD YoU mAKe SuRe The CUvEtTe wAs CleAN?" posts.. not helpful

 

[link81]

i've heard anecdotally that the last few tests of a reagent bottle can be inaccurate.

 

[EW_Fish]

I give my bottle a nice swirl before I grab the 1ml out. Not saying this helps but something I've done over the years

 

[Joedubyk]

i've heard anecdotally that the last few tests of a reagent bottle can be inaccurate.

Ive heard that myself. I really wish my trident was back online so I could check it. When trident and hanna are dialed in they are .02 dkh from each other.

 

[infinite0180]

I make sure the bottle is only open for a few sec each time i use it. I also tighten that sucker really good when i put it away. You want to prevent any evaporation. Usually my old reagent is only 0.1-0.2 higher than a fresh one. I usually double test when changing over to a new one. Be sure to do things exactly the same every time...

 

[Terry Brown]

I reported this issue on a thread titled "Hannah Alkalinity Refill inaccurate" in 2018. I fact, I opened a bottle of new reagent last night and tested. It was showing 7.7 DKH. I have been running at around 8.4. Cross checked with the Salifert and it read 8.4. All I know is the reagent is inconsistent from Lot # to Lot #. I even called Hannah in 2018 and did not get much of a response.

Another thing I noticed is I can take my same sample and retest 3 or 4 times and get a different result with the same sample. I usually just average the results.

I continue to use the Hannah alkalinity tester because I am looking for stability and not so much an exact DKH. As long as the alkalinity is stable all is good.

 

[Joedubyk]

I reported this issue on a thread titled "Hannah Alkalinity Refill inaccurate" in 2018. I fact, I opened a bottle of new reagent last night and tested. It was showing 7.7 DKH. I have been running at around 8.4. Cross checked with the Salifert and it read 8.4. All I know is the reagent is inconsistent from Lot # to Lot #. I even called Hannah in 2018 and did not get much of a response.

Another thing I noticed is I can take my same sample and retest 3 or 4 times and get a different result with the same sample. I usually just average the results.

I continue to use the Hannah alkalinity tester because I am looking for stability and not so much an exact DKH. As long as the alkalinity is stable all is good.

Good to know. I normally get the same result w/ the same re-agent. MAYBE .1 different. That's why I like hanna, it's generally pretty accurate for me. Keeping consistency is usually easy too. Not sure why their reagents can be so far off though?

 

[madweazl]

I believe the deltas to be related to operator error; as another member mentioned, don't leave the bottle open. Before I perform the test, I swirl the bottle once or twice, open it, draw out 1ml, and cap it. I then set the syringe aside (draw in a bit of air so it doesn't drip/leak on my counter), and then collect water for the test. On two occasions I've tested the last bit of one bottle compared to a freshly opened bottle and the results were consistent (one of the two was exactly the same) with different lot numbers. I always use a syringe to fill the cuvette to eliminate eye-balling the water level.

 

[loui]

i sent them an email this morning about the same thing my ALK with old reagent (1 month old) was reading around 6.4 I have been trying to increase my ALK for weeks. When I opened a new bottle I was at 9.0, I started seeing some white under my SPS corals. I am not very happy about it. Have not gotten a reply yet. LOT number 8124 for the reagent.

I usually do swirl the reagent, but I don't cap it during the test. I will start trying this to see what happens.

 

[Joedubyk]

I believe the deltas to be related to operator error; as another member mentioned, don't leave the bottle open. Before I perform the test, I swirl the bottle once or twice, open it, draw out 1ml, and cap it. I then set the syringe aside (draw in a bit of air so it doesn't drip/leak on my counter), and then collect water for the test. On two occasions I've tested the last bit of one bottle compared to a freshly opened bottle and the results were consistent (one of the two was exactly the same) with different lot numbers. I always use a syringe to fill the cuvette to eliminate eye-balling the water level.

I ASSURE you, not operator error. You've just gotten lucky w/ reagent kits and I use a syringe to get 10Ml exact.. .These are the answers I was hoping to avoid

 

[Joedubyk]

i sent them an email this morning about the same thing my ALK with old reagent (1 month old) was reading around 6.4 I have been trying to increase my ALK for weeks. When I opened a new bottle I was at 9.0, I started seeing some white under my SPS corals. I am not very happy about it. Have not gotten a reply yet. LOT number 8124 for the reagent.

I usually do swirl the reagent, but I don't cap it during the test. I will start trying this to see what happens.

Bummer. I mean, if I have to throw the bottle out when it gets low, if that's the answer, then fine. Really am not looking for these types of swings though. I am super SPS dom. I need accuracy

 

[Lorenzo Angotti]

Yes I like using the Hanna checkers, and I would do the same checks that infinite0180 has mentioned above and also when opening your powder sachets ,try not get your fingers in the foil side when emptying into the vials you don’t know what your fingers have been in.

 

[madweazl]

I ASSURE you, not operator error. You've just gotten lucky w/ reagent kits and I use a syringe to get 10Ml exact.. .These are the answers I was hoping to avoid

You may want to avoid them but what do you think is more likely? My confidence in Hanna producing the same product over and over again is much higher than a customers ability to perform the test accurately repeatedly. In two years of logged data, I have a handful of deltas greater than .5 dKh and most of those could be attributed to consumption/dosage changes. This doesn't mean a defective lot isn't possible but certainly not probable.

If you're expecting a different answer from Hanna, don't hold your breath.

 

[Joedubyk]

You may want to avoid them but what do you think is more likely? My confidence in Hanna producing the same product over and over again is much higher than a customers ability to perform the test accurately repeatedly. In two years of logged data, I have a handful of deltas greater than .5 dKh and most of those could be attributed to consumption/dosage changes. This doesn't mean a defective lot isn't possible but certainly not probable.

If you're expecting a different answer from Hanna, don't hold your breath.

bc it doesn't take a rocket scientist to clean the cuvette, not have air bubbles, and use a syringe... There is something else going on here .

 

[saltyhog]

There was a problem a couple of years ago with the foil they used to seal the lids coming in contact with the solution when stored horizontally. I have not had any problem with it for the last couple of years but I test so often my bottle probably doesn't have a chance to get "old".

One thing I always do is use the last test of one bottle and then immediately test again with the new bottle to make sure there isn't a problem. I'm using the older PPM unit and my results are usually exactly the same or at most 1ppm different.

 

[tankstudy]

There was a problem a couple of years ago with the foil they used to seal the lids coming in contact with the solution when stored horizontally. I have not had any problem with it for the last couple of years but I test so often my bottle probably doesn't have a chance to get "old".

One thing I always do is use the last test of one bottle and then immediately test again with the new bottle to make sure there isn't a problem. I'm using the older PPM unit and my results are usually exactly the same or at most 1ppm different.

I do about the same. I save the last two tests and compare it with 2 tests on the new bottles. There have been times when I was off by 1 dkh. I just take note that the new bottle and all the bottles in that lot number, now run about 1 dkh higher. I like to buy 4-5 boxes at a time. I prefer 2 tests over one because sometimes, human error can cause a large difference but with 2 on each bottle for comparison, it can help rule out if it was a human error.

In our lab and its common to have new reagents/tests run slightly higher or lower than previous lots. Sometimes they are spot on which is great too. That's why we test all new lots and adjust our numbers as needed.

I use to keep my DKH around 7 frequently but once I started noticing the difference in the alkalinity between lots, I bumped my dkh to 8 which gives me +/- 1 dkh.

 

[Joedubyk]

Update: I just did a test now, 4 hours shy of 24 hours, as Id like to keep my hand testing the same each day.... 7.1 . So chances are it's the reagent that's off. Trident is coming back til Friday. There is also a chance I am losing .1 to .2 dkh a day. I'll see to night for the full 24 hours...

 

[PatW]

I reported this issue on a thread titled "Hannah Alkalinity Refill inaccurate" in 2018. I fact, I opened a bottle of new reagent last night and tested. It was showing 7.7 DKH. I have been running at around 8.4. Cross checked with the Salifert and it read 8.4. All I know is the reagent is inconsistent from Lot # to Lot #. I even called Hannah in 2018 and did not get much of a response.

Another thing I noticed is I can take my same sample and retest 3 or 4 times and get a different result with the same sample. I usually just average the results.

I continue to use the Hannah alkalinity tester because I am looking for stability and not so much an exact DKH. As long as the alkalinity is stable all is good.

I have noticed the same thing. The Hanna reagent can vary considerably from bottle to bottle. But the readings within a lot group are very consistent often identical from one reading to another. So not so good on accuracy but great one precision.

 

[Terry Brown]

I have noticed the same thing. The Hanna reagent can vary considerably from bottle to bottle. But the readings within a lot group are very consistent often identical from one reading to another. So not so good on accuracy but great one precision.

Pat, that is what I have observed. Reagents seem to be consistent within a lot group.

I test Alkalinity daily and my test procedures are very consistent.

1. Rinse testing vials with Rodi and dry out
2. Rinse vials with sample water from aquarium.
3. Sample 10ml with syringe
4. clean outside of vials after adding the 10ml.
5. Add the reagent and invert the vial 5 times.
5. Line up the testing line on the vial with the front of the Hannah checker.

And if the test seems off, I will fill the 2nd vials with tank water using the steps above, and retest 3-4 times, and use the average of those tests.

 

[Joedubyk]

Update:::: Now that I have a working trident again, it is testing 7.2, exactly the hanna. So at some point, the last few tests from the first batch, were not correct and I lost 1 dkH over a period of time, probably the last 5-6 tests. Luckily, it was a slow leak and hey, the tank is sucking up more alk/cal... can't argue w/ growth!