Traceable seawater standards

[kylarse]

Does anyone have a good source for a NIST tracable seawater standard? I've recently installed a neptune trident, and the reported values after calibration are very different from my hanna checkers. The hanna checkers have been tested against the hanna standards and are in range for the test.

Primarily my neptune alk standard value is said to be 7.85, but testing this solution in the hanna reports 8.28. Neptune specified accuracy to +/-0.05 dkh and hanna specified to +/- 0.3 dkh. The difference in readings is 0.43, so outside of the accuracy ranges of the two methods. I'd like to try a certified standard, to compare methods. The hanna check standard is certified, but the neptune standard is not.

I'm an analytical chemist, so this is an academic exercise. I prefer my equipment to be both accurate and precise.

Thanks



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[superchargedgp]

Youre not gonna get a precise reading with a hobby grade test kit. Even the “holy grail” trident is a hobby test kit


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[kylarse]

Agreed, my point is that I don't trust the Neptune standard, as it has no traceability. I'd like to find a tracable standard to compare. As I mentioned, this is an academic exercise, as I'm a chemist.

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[Sawdonkey]

I was about to ask why you cared since your aquarium won’t show any difference with .4 DkH margin of error. But....then I read your last sentence....

Is measuring alkalinity in a lab setting easy?

This is probably elementary for you and doesn’t really answer your question, but I really like this article by my reef chemistry hero Randy Holmes Farley:

Chemistry and the Aquarium: What is Alkalinity?

Randy provides an overview of alkalinity as to why it's important, how it's measured, and how can it be tested.

www.advancedaquarist.com