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Thanks. I found this reply useful.A more extended discussion would be to first define gold standard. To me, as a scientist, that term would imply high accuracy and have no weighting to convenience or ease of use or cost. Others here are using the term differently, and that’s of course, fine.
In the truest sense, none of the Hanna devices are the gold standard by my definition. No science lab would use them for important measurements. Look at what companies such as Oceamo use to add to their icp data. They are not Hanna checkers. They are lab instruments of various sorts, such ion chromatography.
I have nothing in particular against most of the Hanna checkers (although I think the calcium checker is poorly designed and the conductivity meter is not even close to the best available). They may often be the best choice for some folks for some parameters.
While I think the case is often overstated, I do agree that since exact and “correct” values are often not needed by reef aquarists, reproducibility of even somewhat incorrect answers is valuable and may be fine.
I do think that folks using them should always check the Hanna specs for accuracy. Several times a week I am pointing out to folks that even Hanna says the values they are seeing in some scenario are not exact enough to support some claim or concern. The digital precision gives folks a false sense of accuracy.
For alk, I would claim a real titration of a large volume of tank water with a quality standard acid is the gold standard. That’s one of the few high accuracy tests that folks can inexpensively do at home.
For salinity, there are a few options, including high precision glass hydrometers and conductivity meters. All need to be validated for accuracy, IMO.
Your observation that “reproducibility of somewhat incorrect answers (inaccurate measurements) is valuable” speaks to the idea that you need to know how accurate you have to be to select the correct measurement method. The notion of a gold standard method might be irrelevant. Matching accuracy requirements is what is most important (@Rick Mathew often speaks to this ). And that is why an important measurement, one that requires high precision and accuracy, would not utilize a Hanna Checker.
There might be analogies to financial accounting. There are times when to-the-penny accounting might be important, say a lemonade stand, and then there are times when rounding to the nearest $1000 is fine, say Randy’s 2025 budget