Hanna checkers accuracy question.

nc4217

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Hi all

Wanted to raise a question about Hanna in general hoping someone may know the scientific answer. Been using Hanna for a while no issues but while sitting around bored today, decided to actually read through the entire manual of the URL phosphate. Would anyone know why they math in the manual for accuracy does not align. For example.The manual for this checker shows

+- .02ppm +- 5% @25c/77f

If for example my phosphate level was 0.8 a 5% variance is .04 and if that is the case why mention the +- .02ppm. Or are you really suppose to be interpreting there results as the min of the .02. Or 5% of result. And vice versa is my reading as .1 a 5% variance is only .005 and therefore then need to max the .005 and .02 to determine which variance to apply to the checker result. Thoughts?

This does seem to be common across other checker and I keep my tank at 78f so would images temp in the vial drops a tick during testing can comes close to the 77f also mentioned.

Thanks
 

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Well if you want to get scientific with it, these are hobby grade tests and will not pin point the exact number. As for their claims it does seem pretty weird they'd include a percentage and a ppm variance. Especially when they're so far apart from each other. I understand the want for accuracy, but we just won't get it from these hobby grade testers. Hell even icp results are about the same deviation especially on phosphates (what I assume the checker you're using).
Phosphates are a tough one to test as what you're doing (with the test) is changing the elements to something different in order to get a color reading.
Unfortunately, you kinda just have to go with whatever it tells you and just shoot for the same results each time. You can do tests back to back and it will more than likely be different each time.
 
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nc4217

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Sorry to clarify when I say accaracy not talking about getting pinpoint just trying to get to an Accurate range based on the variance of each meter. But when the math does not align it has me scratching my head a bit.
 

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ULR phosphate Hanna Checker has an accuracy of +/- .02 ppm. So if your reading is ".04 ppm", then it is really .02-.06 ppm.
 
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nc4217

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ULR phosphate Hanna Checker has an accuracy of +/- .02 ppm. So if your reading is ".04 ppm", then it is really .02-.06 ppm.
Yes, get that, question is why also say right next to that in the manual at 77f it has a 5% accuracy in which a +- 5% spread of a .04 reading would be .038 - .042. And even with this if you wanted to floor and ceiling the range would be .03-.05 and only be a +- 0.01 accuracy which does not match +- 0.02. Is Hanna basically saying you can make your reading more accurate by testing at 77F exactly
 
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nc4217

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ULR phosphate Hanna Checker has an accuracy of +/- .02 ppm. So if your reading is ".04 ppm", then it is really .02-.06 ppm.
Yes, get that, question is why also say right next to that in the at 77f it has a 5% accuracy in which a +- 5% spread of a .04 reading would be .038 - .042. And even with this if you wanted to floor and ceiling the range would be .03-.05 and only be a +- 0.01 accuracy which does not match +- 0.02. Is Hanna basically saying you can make your reading more accurate by testing at 77F exactly
 

REEFRIED!

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Hi all

Wanted to raise a question about Hanna in general hoping someone may know the scientific answer. Been using Hanna for a while no issues but while sitting around bored today, decided to actually read through the entire manual of the URL phosphate. Would anyone know why they math in the manual for accuracy does not align. For example.The manual for this checker shows

+- .02ppm +- 5% @25c/77f

If for example my phosphate level was 0.8 a 5% variance is .04 and if that is the case why mention the +- .02ppm. Or are you really suppose to be interpreting there results as the min of the .02. Or 5% of result. And vice versa is my reading as .1 a 5% variance is only .005 and therefore then need to max the .005 and .02 to determine which variance to apply to the checker result. Thoughts?

This does seem to be common across other checker and I keep my tank at 78f so would images temp in the vial drops a tick during testing can comes close to the 77f also mentioned.

Thanks
Your phosphate is 0.8??? That seems high
 

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