Hanna Checker - inaccurate?

[oldedb]

Purchased a Hanna Alkalinity unit less than 3 months ago... Fell in love with it b/c it's so **** easy. Come to find out it is measuring much lower than my salifert kit and my results from Elos and Salifert at LFS. Today my Hanna read 6.2 and my salifert read 9.3.

What sucks is I have been dosing off of the results of my Hanna. Struggling to get Alk up to 8 but all the while I've had all in the 12 range!

Anyone had issues with these? Can you calibrate them?


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[bcavalli]

I don't believe you can calibrate them. However, I have found that the reagents have a tendacy to go bad after a few months. I would probably suspect this might be your issue.

 

[russ-iv]

i asked about hanna checkers last week and it was determined alk can be off 1 dkh. phosphorus was as accurate as you can get. the alk was higher in the test.

have you used the calibration solution?

 

[oldedb]

I haven't tried calibration solution? Where can I grab some of that?
My belief is that the measurements are consistent and I have used 2 bottles of reagent. They are consistently low than the actual Alk by roughly 3 dkh.
I also forgot to mention that I religiously rinse the vials once I get the results and I let them air dry. I have read where the vials can stain and impact readings.


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[russ-iv]

oldedb;1041461 wrote: I haven't tried calibration solution? Where can I grab some of that?
My belief is that the measurements are consistent and I have used 2 bottles of reagent. They are consistently low than the actual Alk by roughly 3 dkh.
I also forgot to mention that I religiously rinse the vials once I get the results and I let them air dry. I have read where the vials can stain and impact readings.


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http://m.jjstech.com/hi755-11.html">http://m.jjstech.com/hi755-11.html</a>

prolly a better place to get it than the one i posted.

 

[bcavalli]

oldedb;1041461 wrote: I haven't tried calibration solution? Where can I grab some of that?
My belief is that the measurements are consistent and I have used 2 bottles of reagent. They are consistently low than the actual Alk by roughly 3 dkh.
I also forgot to mention that I religiously rinse the vials once I get the results and I let them air dry. I have read where the vials can stain and impact readings.


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Actually it's not calibration fluid. Its standards that measures your Hanna checker for Color accuracy. You can get the standards on the Hanna website for about $12. I found that if your checker doesn't immediately go to C2 (flashes for more a few seconds) then usually the vial is dirty and I'll get an inaccurate measurement. To keep the vials clean (pain in then butt, till I read about a few people's suggestions). I keep a sealed bag of screen cleaning wipes. They work really well for cleaning the outside. After I finish the test, I rinse the vial out with RO water and refill it with RO water for storage.

 

[oldedb]

Brett - do the instructions specifically say that the vials should be stored w/ Rodi in them? I typically air dry them and rotate vials every test. My checker typically goes from C1 to C2 pretty quickly. Kind of odd b/c visually the vials look like they are in good shape.


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[bcavalli]

oldedb;1041537 wrote: Brett - do the instructions specifically say that the vials should be stored w/ Rodi in them? I typically air dry them and rotate vials every test. My checker typically goes from C1 to C2 pretty quickly. Kind of odd b/c visually the vials look like they are in good shape.


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The instructions don't say that. But, I picked up that tip from a few users on another forum. It helps keep the inside of the glass from spotting. I've had bad bottles of reagents as well, that gave wacky results. Your welcome to borrow my standards kit or bring over your checker and we can test it against the standards.