hanna alk checker post your results

[JimWelsh]

My full original post was simply trying to help improve your study. By testing the Hannah checker with water of a known dkh, against itself with and without the extension, vs. against Salifert will help you isolate (but not completely) what I believe you are trying to prove - that the Hannah checker is more accurate without the extension. Bringing in Salifert to prove this just adds another variable. How do you know the variation you are seeing isn't from the salifert test?

"More precise" without the extension, not "more accurate".

If you want to quantify precision, then you will take the same sample, and measure it repeatedly (at least three times, and hopefully more) using the same method. A 95% confidence interval for the method will be appx. two times the standard deviation. It isn't really possible to ascertain the precision of a method by sampling a dynamic system like a reef aquarium at various different times.

 

[CMO]

"More precise" without the extension, not "more accurate".

If you want to quantify precision, then you will take the same sample, and measure it repeatedly (at least three times, and hopefully more) using the same method. A 95% confidence interval for the method will be appx. two times the standard deviation. It isn't really possible to ascertain the precision of a method by sampling a dynamic system like a reef aquarium at various different times.

Don't disagree with that. I just don't understand the comparison against Salifert here, which from what I can tell is being deemed the reference sample.

 

[dferran1]

FWIW I'm of the opinion that the correct endpoint color for the Salifert alk test is better described as a "lavender" color. Going all they way to pink is overshooting the true endpoint. For an example of the color I'm trying to describe, please see here: Salifert Test Kit and Hanna Checker Results for Alkalinity

For a more detailed explanation of why I think this is so, please read through the following thread starting here: Salifert KH/Alk testing help

Jim, thanks for the links. Those are excellent. So essentially the endpoint falls at a pH of between 4.2-4.3?

 

[Art2249]

My full original post was simply trying to help improve your study. By testing the Hannah checker with water of a known dkh, against itself with and without the extension, vs. against Salifert will help you isolate (but not completely) what I believe you are trying to prove - that the Hannah checker is more accurate without the extension. Bringing in Salifert to prove this just adds another variable. How do you know the variation you are seeing isn't from the salifert test?

I am seeing very little variation! 1 variation!

 

[Art2249]

I am seeing very little variation! 1 variation!

Plus you have the misconception that I am trying to prove ANYTHING! Just gathering information!!!

 

[Art2249]

I dont't know what happen to science from the time I was a kid to now. I remember science being that you gather information and learn, i don't remember trying to "prove" anything. We are here trying to learn. That's all.

 

[dferran1]

Plus you have the misconception that I am trying to prove ANYTHING! Just gathering information!!!

Guys, it's just a discussion. Art is right. Not everybody here has a scientific background, and that needs to be respected. People with little to no scientific training, following just the instructions on the test kits, have achieved some amazing tanks. Additionally, while I found the links provided by Jim to be interesting, I do not think it is practical for the average person keeping a reef tank, for them to be concerned about an error of a few tenths of a dKH when testing alkalinity. Personally, I have access to the equipment and I have the background to be able to go and do a potentiometric titration, assemble a titration curve, and say, quantify the error in my determination. ( I'm an organic chemist.) I can go to my colleagues in the instrumental analysis laboratory, and they can likely obtain a value of carbonate hardness down to many decimal places. However, I don't have the desire to. My corals are growing fine.

Just realize there is some error present in testing with hobby grade test kits, and aim for stability over time. A reef tank can thrive over a wide range of parameters, so long as those parameters are kept stable.

 

[CMO]

I'll play ball and collect this data for you tonight when I test. I'll test the same water on the same Hannah checker back to back with and without the extension.

 

[Art2249]

Don't disagree with that. I just don't understand the comparison against Salifert here, which from what I can tell is being deemed the reference sample.

Let me clarify. it's my fault for not being more precise at first. I don't have a reference solution. I was using salifert to test against hanna. if I were a true scientist, which I am not, I would use a reference solution against hanna (without the syringe extension) and have a conclusion. Maybe someone out there, in the vast universe, has used the hanna checker without the syringe extension against a reference solution and established a definitive result. Please post your findings.

 

[JimWelsh]

Jim, thanks for the links. Those are excellent. So essentially the endpoint falls at a pH of between 4.2-4.3?

If you trust Dickson, Millero, and my mathematical interpretation, then, yes.

 

[JimWelsh]

I dont't know what happen to science from the time I was a kid to now. I remember science being that you gather information and learn, i don't remember trying to "prove" anything. We are here trying to learn. That's all.

I think that the kind of thing you are doing is a great thing for any hobbyist to do. Being curious, paying careful attention, and writing things down are all good things to do. Over the past 10 years or so, I've gone from being a totally clueless newbie in the hobby to, being, well, at least not so clueless, as a result of following that curiosity where it took me. More power to you!

 

[CMO]

Exact same testing procedure was used for each with the same water. Wipe vials with micro fiber cloth and position the 10ml mark forward.

Results without extension - 7.9 dkh
Results with extension - 7.8 dkh

FWIW, I have two alk Hannah checkers and have never seen more than a 0.1 dkh discrepancy either among them or in back to back test across the same device. I believe many of the reports of Hannah checker inconsistency is either due to user error (inconsistent test procedure, cleaning, etc.) or a defective device.

 

[ckalupa]

If you use the Hanna provided extension, 1Ml won’t even enter the main syringe. The result should be identical. 1Ml is 1Ml. No waste. Extension needs to be installed tightly also.

Besides- any small variations likely can be described as within the normal limits of the Hanna meter itself. Tester error too. Tank water is an imperfect control sample IMO.

 

[homer1475]

1ml is 1ml with or without the extension. Why is this even a debate?

Hanna has even stated that the tip is not needed and all it does is keep the syringe clean.

 

[nova65ss]

I've been using my Hanna alk tester for five plus years no extension. As long as you pull the same amont each time what does it matter. I pull the reagent up to the 1 mil line and get it as close to even as possible always works never had an issue.

 

[Randy Holmes-Farley Verified Community Expert]

I dont't know what happen to science from the time I was a kid to now. I remember science being that you gather information and learn, i don't remember trying to "prove" anything. We are here trying to learn. That's all.

Just as an aside, I'll pontificate a bit on "science" lol

The scientific method is:

Generate a hypothesis, and design and perform an experiment to test the hypothesis. This is, by definition, the scientific method. You can read it in more detail here:

Steps of the Scientific Method
https://www.sciencebuddies.org/science-fair-projects/science-fair/steps-of-the-scientific-method

 

[Randy Holmes-Farley Verified Community Expert]

Let me clarify. it's my fault for not being more precise at first. I don't have a reference solution. I was using salifert to test against hanna. if I were a true scientist, which I am not, I would use a reference solution against hanna (without the syringe extension) and have a conclusion. Maybe someone out there, in the vast universe, has used the hanna checker without the syringe extension against a reference solution and established a definitive result. Please post your findings.

As a second aside, it is a perfectly valid scientific hypothesis for a scientists to test as to whether the two tests agree or not. No reference is needed for that.