inconsistant readings KH

wishntoboutside · Jan 22, 2018

Hello,

I have used your product for years and I am now finding an issue with new reagents. I used up my old reagent and opened up a new box. Instantly the results were different and I did not think much of this until the problem started. Now that I had a tank issue this is what i am finding. I have used two new regent solutions and those test are consistent with each other however when I test on Salferit test kits. new box and old box i get completely different readings from what my checker says. the difference to me is huge as it is 1.3 DKH. I don't know what test is right or wrong. I have now ordered brand C to compare but something here is wrong. Are there any bad batches on your end that I may have in my hands. In the past my Hanna and Salferit test were always pretty close.

Thanks for your help

MTBake · Jan 22, 2018

My alk checker reads 1 dkh lower than my salifert kit. I just got my checker 2 weeks ago. I got 8.2 dkh with my checker and 9.2 with salifert and 9.4 with red sea yesterday. I was thinking they'd be closer to each other myself. Not sure if that helps any. I'm still new to Hanna products but not the other 2.

Stephen Glover · Jan 22, 2018

I picked up my first hanna alk checker a few weeks back and it matches my salifert kit perfectly.
Lot 6799
Exp 11/18

MTBake · Jan 22, 2018

Stephen Glover said:
I picked up my first hanna alk checker a few weeks back and it matches my salifert kit perfectly.
Lot 6799
Exp 11/18

I have that same lot still wrapped in the box. I'll have to try it tomorrow to see how it compares to what came with my checker. Lot: 6876, exp: 12/18 came with my checker.

Hanna Instruments · Jan 25, 2018

wishntoboutside said:
Hello,

I have used your product for years and I am now finding an issue with new reagents. I used up my old reagent and opened up a new box. Instantly the results were different and I did not think much of this until the problem started. Now that I had a tank issue this is what i am finding. I have used two new regent solutions and those test are consistent with each other however when I test on Salferit test kits. new box and old box i get completely different readings from what my checker says. the difference to me is huge as it is 1.3 DKH. I don't know what test is right or wrong. I have now ordered brand C to compare but something here is wrong. Are there any bad batches on your end that I may have in my hands. In the past my Hanna and Salferit test were always pretty close.

Thanks for your help

MTBake said:
My alk checker reads 1 dkh lower than my salifert kit. I just got my checker 2 weeks ago. I got 8.2 dkh with my checker and 9.2 with salifert and 9.4 with red sea yesterday. I was thinking they'd be closer to each other myself. Not sure if that helps any. I'm still new to Hanna products but not the other 2.

Hello thank you for reaching out and for being a valued Hanna customer.

If you are concerned with your reagent lots please email [email protected] with your reagent Lot#. You may also call (401) 765-7500 Monday-Friday 9am to 5pm EST for assistance with any Hanna products.

We have had no complaints regarding Alkalinity reagents and there are no reported problems.

tgionet · Mar 20, 2018

MTBake said:
My alk checker reads 1 dkh lower than my salifert kit. I just got my checker 2 weeks ago. I got 8.2 dkh with my checker and 9.2 with salifert and 9.4 with red sea yesterday. I was thinking they'd be closer to each other myself. Not sure if that helps any. I'm still new to Hanna products but not the other 2.

I have 7041 currently and it reads 6 ppm lower than the last batch I had which was 6 ppm lower than the prior batch. I tested all 3 batches against each other. (I always test the reagents against my current bottle when I open a new one)

MTBake · Mar 20, 2018

tgionet said:
I have 7041 currently and it reads 6 ppm lower than the last batch I had which was 6 ppm lower than the prior batch. I tested all 3 batches against each other. (I always test the reagents against my current bottle when I open a new one)

I also compare reagents to the lot I'm currently using before it runs out. My reagent lots have checked within .2 DKh of each other. I'm only on my 3rd lot since I got my checker though. Guess I should say third bottle, as it's the same lot as my second bottle.

Edit:
I have the calcium checker and low range phosphorus checkers on the way as well. Really like the ease of use and number readout(versus trying to match colors that look the same to me)

Hanna Instruments · Mar 21, 2018

On the HI772 dKH Alkalinity Checker the accuracy statement = Accuracy @ 25°C/77°F ±0.3 dKH ±5% of reading. . The major advantage of using a colorimeter, or digital test, is you can measure accuracy without subjective human error (so long as instructions are followed).

It could be possible that over time using a dirty syringe with dried reagent over and over again can potentially impact the results/chemistry of the reagent.

Make sure the reagents are not contaminated in any way either with saltwater or RODI water.

Also visit our blog to make sure you are following our 8 checker best practices such as indexing the cuvette in the same position every time, removing any air bubbles, finger prints or smudges and using separate pipettes/syringes for freshwater and saltwater.

If you are ever concerned with the accuracy of your Checker, you can purchase a standard to make sure the device is preforming within its accuracy statement.

http://hannainst.com/hi772-11-marine-alkalinity-dkh-checkerr-hc-calibration-set.html

MTBake · Mar 21, 2018

Hanna Instruments said:
On the HI772 dKH Alkalinity Checker the accuracy statement = Accuracy @ 25°C/77°F ±0.3 dKH ±5% of reading. . The major advantage of using a colorimeter, or digital test, is you can measure accuracy without subjective human error (so long as instructions are followed).

It could be possible that over time using a dirty syringe with dried reagent over and over again can potentially impact the results/chemistry of the reagent.

Make sure the reagents are not contaminated in any way either with saltwater or RODI water.

Also visit our blog to make sure you are following our 8 checker best practices such as indexing the cuvette in the same position every time, removing any air bubbles, finger prints or smudges and using separate pipettes/syringes for freshwater and saltwater.

If you are ever concerned with the accuracy of your Checker, you can purchase a standard to make sure the device is preforming within its accuracy statement.

http://hannainst.com/hi772-11-marine-alkalinity-dkh-checkerr-hc-calibration-set.html

Thanks for the reply!

I'm confident in the readings I get from my alkalinity checker. I really like it! So much that I ordered the calcium and low range phosphorus checkers as well. They were just delivered in fact

Can't wait to get home and try them out! Thanks for great products, Hanna!

I agree on watching the videos as well. They are very helpful!

Mindi · May 28, 2018

I always compare the results from my almost empty Alk reagent bottle and my new replacement bottle which is always from a different batch. I happened to do this today....the two readings were 160 and 159....I would call that super consistent...both 3.2 meq/l

A777flygirl · Jul 5, 2018

Hanna Instruments said:
Hello thank you for reaching out and for being a valued Hanna customer.

If you are concerned with your reagent lots please email [email protected] with your reagent Lot#. You may also call 401-450-7500 Monday-Friday 9am to 5pm EST for assistance with any Hanna products.

We have had no complaints regarding Alkalinity reagents and there are no reported problems.

This is a Wrong phone number...