New hanna alk reagent testing way off

Mrx7899 · Jan 27, 2020

I just got two new reagents and they are testing way off almost 1dkh off. Just wondering if you had a recent batch of reagents go bad like you did a couple years ago. They are both lot 8414 I ordered 3 bottles the other bottle is lot 7993 and that is testing fine.

Mrx7899 · Jan 28, 2020

Emailed them and they got back to me they are sending out new bottles. Happy with their costumer service.

miyags · Jan 28, 2020

I hate when this happens.I never know which one is correct. And I won't spend 50$ to have a lab test it.

hllb · Jan 28, 2020

Curious what you were testing against? It wouldn't occur to me to verify a new bottle of reagent but sounds like I should.

tankstudy · Jan 28, 2020

Generally, I save 2 tests on the previous bottle or lot and then run 2-3 tests on the new bottle/lot to compare. Sometimes they maybe off 1 dkh or just +/- 0.5 dkh. However, I just readjust the number I'm targeting for.

Unless, the new reagent is off by a huge number I'm not too concerned.

ajhudson15 · Jan 28, 2020

the problem with this is, isn't the accuracy 0.4? if that's the case you could be at 8.0 and one test reads 7.6 and the other could read 8.4. looks like its off a lot but its within the +- accuracy

Dempsey941 · Jan 28, 2020

ajhudson15 said:
the problem with this is, isn't the accuracy 0.4? if that's the case you could be at 8.0 and one test reads 7.6 and the other could read 8.4. looks like its off a lot but its within the +- accuracy

Accuracy is within 0.04, so if it reads an 8 it could be 8.04-7.96

ajhudson15 · Jan 28, 2020

Dempsey941 said:
Accuracy is within 0.04, so if it reads an 8 it could be 8.04-7.96

ahh my bad I forgot a 0

PatW · Jan 28, 2020

You can make a standard. I am thinking of making one. First I add enough sodium chloride to 1 gallon of RODI to yield a specific gravity of 1.025. i use BRS soda ash. I add 5.7 ml of that to my salt solution to yield a standard of 8.0 DKH. Now since my soda ash additive is 2.5 cups of soda ash into 1 gallon of RODI, it is probably off a bit. It should be close enough for my purposes. if I test each new bottle against the std, I will know if it is off and by about how much from the previous one.

Williamson’s Reef · Jan 28, 2020

I’ve had some bad Hanna regents myself. Installed a trident showed 8.8 alk and the Hanna showed 6.8 Alk. Ran multiple test still way off. Opened up a new hanna regent and boom.. matched the trident. I kept upping my dosing and was struggling to raise alk Previously.

Brian_68 · Jan 28, 2020

Looks like the accuracy is +/- 5% of reading so at 8 it is 7.6 to 8.4. If it is 7 or 8 I am happy in general, not concerned with 0.1 levels.

Saltwater Aquarium Alkalinity Colorimeter (dKH) Checker® HC

The HI772 Marine Alkalinity Checker®HC (Handheld Colorimeter) provides a simple, accurate and cost-effective way to measure alkalinity as dKH (degrees of calcium hardness).

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madweazl · Jan 28, 2020

Dempsey941 said:
Accuracy is within 0.04, so if it reads an 8 it could be 8.04-7.96

It isn't capable of reading .0X.

Dempsey941 · Jan 28, 2020

madweazl said:
It isn't capable of reading .0X.

Does it if you are using the ppm checker

X-37B · Jan 28, 2020

My hanna used to be within .3 higher of salifert. It is now .7-1.0 higher with new reagent. I bought the standard and it is reading 5.04 with the standard being 5.0 dkh. I run 8.0 dkh and salifert reads 7.3 now running it to pink. If I run it to lavender it is even lower. I have always ran salifert to pink and it was within .3 of hanna.
As long as its stable im not to concerned. Still would like to know actual dkh though.
Think I will make a standard and see where both fall.

madweazl · Jan 28, 2020

Dempsey941 said:
Does it if you are using the ppm checker

Nope.

Brian_68 · Jan 28, 2020

Biggestfish said:
I’ve had some bad Hanna regents myself. Installed a trident showed 8.8 alk and the Hanna showed 6.8 Alk. Ran multiple test still way off. Opened up a new hanna regent and boom.. matched the trident. I kept upping my dosing and was struggling to raise alk Previously.

I am not sure what the accuracy of the Trident is since they do not spec it. They only spec precision of 0.05 dkh but that only means how it differs from one reading to the next but that reading could be way off the truth even though it consistently reads the same reading after reading. Precision and accuracy are way different.