Problem with Hanna alk reagent

[Nate Chalk]

Most of these errors are due to contamination of the bottle or the reagent. I’m not saying that there can’t be differences in the reagents but there are so many things that can affect the test that it’s often not the reagent that is at fault.

Here’s how I have got more consistent results.

1) Always flush the vials out with RODI water after use and store them full of RODI.

2) Clean the vials thoroughly before the initialization and before the test.

3) Always use a single vial (not one for the initialization and a different one for the test) and make sure it is always put in the checker the same way round (I put the 10ml mark facing me).

4) Keep the reagent bottle closed as much as you can.

5) Count the number of tests (I mark them on the bottle). The bottle is good for 25 tests but there is more than 25ml fluid in there. Once I’ve done the 25, I throw the bottle away.

6) Possibly a controversial one, but I never clean the syringe and I don’t let the tip touch anything. I couldn’t guarantee that it was completely dry after cleaning, and think this may have been affecting my results.

7) It has been reported that some of the 10ml lines on the vials are not accurate. I haven’t had this problem but, if you are getting inaccurate results, it might be worth measuring the sample water with a syringe.

8) Make sure the battery is not flat.

If you’ve done all of this and there are still big errors, then I would start question either the reagent or the colorimeter.

Second this methodology, i always shake the reagent as well not vigorously.

 

[markwayts]

Hello all. I've been trying to keep a closer eye on my alkalinity lately. I'm using a hanna dkH checker. Last night I finished a bottle of reagent and had a reading of 8.6. today I come home and test with a new bottle and my reading is 9.8. I'm like what the heck. I'm not dosing so why did it go up. So I open another box and test and its 12.7. Now I'm really confused not to mention a little upset because at this point I have no clue what my readings really are. The checker has been the only thing I have been using and now I'm wondering was the first bottle accurate, the second or the third? Does anyone have any idea how I should proceed from here to get an accurate reading? Is there another method for testing alk that would be recommended to try and get this figured out? I seem to loose quite a few corals now and then for no reason and in this tank I can not even grow zoas or green star polyp, mushrooms or ricordia along with other "easy to grow" corals that other folks can't seem to get rid of and now I'm wondering if it has been because of bogus alk readings. I've been using Hanna checkers for alk and PH for over a year and now I'm really confused on how to proceed. I only have a few LPS and a couple of leathers in this tank. I have quite a few nice LPS and a few SPS srags in another tank that are doing good but now I'm afraid to even test that one.

I have certainly had new bottles be a whole degree off (ie. old bottle reads ten new bottle reads nine. Not sure why but i always test my new and old reagent beffore i switch and verify with a different companies test kit. The actual number isn't too important if it's in the safe range. Stability is most important.

 

[taricha]

my $0.02
The most simple and fundamental measurement of Alk is a titration. It's absurdly repeatable.
That hanna was able to use a reaction to produce a linear color change for alkalinity level has always seemed to me like one of those things that shouldn't work. So I'm impressed that it kinda does.
I love hanna kits but I don't and wouldn't use their alk checker, because I'd like to be able to drill down and get more precise alk than what that method can allow. Even their claimed uncertainty for the alk test is notably higher than their other tests.

 

[exnisstech]

I'll just stick with the salifert and maybe buy another brand for comparison. I know it's more about consistency than chasing a number but I'd still like to know what the real number is just for trouble shooting if stuff starts looking abnormal. Thanks for all the replies.

 

[homer1475]

In 6 years of using a hanna checker for ALK, have never had wild results from bottle to bottle.

I'm sure it happens, but in 6 years I haven't seen it.

I cross check the hanna every now and then with a salifert kit, pretty much dead on with each other.

 

[Woodyman]

In 6 years of using a hanna checker for ALK, have never had wild results from bottle to bottle.

I'm sure it happens, but in 6 years I haven't seen it.

I cross check the hanna every now and then with a salifert kit, pretty much dead on with each other.

Agreed, if your cross checking then no need to worry, I have had a bad bottle, but these things happen. I would at a minimum cross check every new batch/bottle.

 

[HuduVudu]

This seems to be an interesting solution:

Marine Alkalinity (dKH) Checker® HC Calibration Check Set

The Marine Alkalinity (dKH) Checker® HC Calibration Check Set - HI772-11 provides a stress-free, straightforward way to ensure your handheld colorimeter is working properly and providing accurate alkalinity measurements.

www.hannainst.com

 

[exnisstech]

Ok I decided to have another go at it since I really like the convience of the Hanna checker. I took the advise of some folks who replied. I made sure the vial is clean and used the same vial for all test. I also measure the 10 ml with a syringe rather than using the mark on the vial. Interesting enough the line is not a full 10ml when measures. It's a bit less. Compared to salifert reading of 10.5 the Hanna read 9.7. Fully acceptable to me. So I tested both bottles of reagent against each other and both gave the same result of 9.7. Obviously I must have been doing something wrong when I originally performed the tests. Probably using the line on the vial and my old eyes vs measuring with a syringe I suspect. I just wanted to update this so as not to steer people away from the Hanna tester as it is a nice convient way to check alk.

 

[moz71]

Ok I decided to have another go at it since I really like the convience of the Hanna checker. I took the advise of some folks who replied. I made sure the vial is clean and used the same vial for all test. I also measure the 10 ml with a syringe rather than using the mark on the vial. Interesting enough the line is not a full 10ml when measures. It's a bit less. Compared to salifert reading of 10.5 the Hanna read 9.7. Fully acceptable to me. So I tested both bottles of reagent against each other and both gave the same result of 9.7. Obviously I must have been doing something wrong when I originally performed the tests. Probably using the line on the vial and my old eyes vs measuring with a syringe I suspect. I just wanted to update this so as not to steer people away from the Hanna tester as it is a nice convient way to check alk

More important just to make sure using same amount every time. I don’t care if exactly 10 ml as long as same amount every time. And I had differences between bottles! hey these are hobby grade. I don’t expect perfection. Go with what makes you comfortable! I also continue to use Hanna because pure simplicity. If I see something crazy I just check with another kit

 

[Tamberav]

I had this happen twice in many years using hannah. I sent them lot number and they replaced both.

 

[moz71]

I had this happen twice in many years using hannah. I sent them lot number and they replaced both.

Good to know thank you. I am always too lazy to do that!

 

[HuduVudu]

Just FYI after many many many years of using Salifert. I am switching. The reason that I am switching is that (I believe) Salifert has changed their alk reagent. The color is definitely not the same of the years past it is greener not the blue that I am used to. The reason that this matters is that I am struggling to find where the titration is happening. I am definitely not happy with this turn of events.

 

[DE FISH]

Ok I decided to have another go at it since I really like the convience of the Hanna checker. I took the advise of some folks who replied. I made sure the vial is clean and used the same vial for all test. I also measure the 10 ml with a syringe rather than using the mark on the vial. Interesting enough the line is not a full 10ml when measures. It's a bit less. Compared to salifert reading of 10.5 the Hanna read 9.7. Fully acceptable to me. So I tested both bottles of reagent against each other and both gave the same result of 9.7. Obviously I must have been doing something wrong when I originally performed the tests. Probably using the line on the vial and my old eyes vs measuring with a syringe I suspect. I just wanted to update this so as not to steer people away from the Hanna tester as it is a nice convient way to check alk.

Use 0.00 scales to measure your water 1.025sg = 10.25 grams 1.026 = 10.26 grams that way you have a consistent measurement

 

[exnisstech]

Use 0.00 scales to measure your water 1.025sg = 10.25 grams 1.026 = 10.26 grams that way you have a consistent measurement

Good suggestion but the only scale I have is a postal scale and it will not do partial grams. I don't want to buy one just to do my alk testing

 

[Randy Holmes-Farley Verified Community Expert]

Just FYI after many many many years of using Salifert. I am switching. The reason that I am switching is that (I believe) Salifert has changed their alk reagent. The color is definitely not the same of the years past it is greener not the blue that I am used to. The reason that this matters is that I am struggling to find where the titration is happening. I am definitely not happy with this turn of events.

If you have a pH meter, you can gauge the exact color based on the pH. The endpoint is about pH 4.3.

 

[nereefpat]

my $0.02
The most simple and fundamental measurement of Alk is a titration. It's absurdly repeatable.
That hanna was able to use a reaction to produce a linear color change for alkalinity level has always seemed to me like one of those things that shouldn't work. So I'm impressed that it kinda does.
I love hanna kits but I don't and wouldn't use their alk checker, because I'd like to be able to drill down and get more precise alk than what that method can allow. Even their claimed uncertainty for the alk test is notably higher than their other tests.

I completely agree. Alkalinity is, by definition, a titration. I don't know why anyone would think a colorimeter would be better for this.

Hanna makes the best hobby kits for some things, like phosphate and copper. But that doesn't mean that it makes sense to use a colorimeter to measure alk.

 

[HuduVudu]

If you have a pH meter, you can gauge the exact color based on the pH. The endpoint is about pH 4.3.

OMG this is VERY helpful.

Thank you Randy

 

[reeftivo]

All I can say is that I haven’t had anything like a 2DKH difference between 2 bottles.

Maybe I’ve just been lucky.

I haven't either but i have noticed that some of the syringes that come with a new bottle will draw more or less reagent from the bottle. Not sure if it is the syringe seals or the tip that connects, but more or less reagent definitely can have a affect on the readings. i got a pretty close confirmation with my Salifert kit when using the syringe i've been using 4 bottles ago, so i keep using that syringe and tip until the numbers rub off LOL.

 

[Lasse]

Copy from my answer in another thread

There is a way to hinder the Hanna alk to show lesser and lesser dKH (or ppm for that meter) with age of open reagent bottle. I had the same story - 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 1/2 a year 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

Sincerely Lasse

 

[Koigula]

It’s the reagent. Convinced. I changed bottles and have big differences. I see clumps coming out of some bottles. 2 times water turned yellow.

It absolutely is the reagent for me as well.

I used Hanna reagent bottle with batch #X and can get 154 ppm, 154 ppm, 153 ppm using a 10.0 cc autopipetter and triple rinse glass ware and micro clothe. When I got to new batch #Y I get 162, 163, 162 ppm etc. SO with this bottle I just target 163 ....

I would be fine with wrong but consistent. I am probably going to ditch this device and just tritate with a standard method. It only takes a few mins if set and ready to go. Between this and my salt being recalled it is a bit frustrating. I may move beer fridge in basement to storage room where I test to store Hanna reagent. I hate to buy more stuff when I have reagent.

On the plus side SPS are definitely settled down and starting to take off.