K test

[sowellj]

So I have been working on adjusting my K levels, and the KZ test is quite difficult to read. I am thinking of modifying it a bit. As is, the test works by measuring turbidity. You look through a cloudy vial until you can no longer see a colored bar and that is your level. I plan on making a K standard at 390 mg/L, which is the natural seawater value. I'll use KCl, to do this. Since KCl is ~ 52% weight K, this works out to roughly 7.5 mg KCl in 10 mL of water. The KZ test uses a peach color strip, which gets slightly darker the more concentrated K is. I was thinking of using a black/blue strip, (something easily visible) and then comparing my sample with the standard. You could also make a few other standards up, just to get an idea of what the value, is, as this will only give qualitative results. Anyone see a reason why this wouldn't work?

[Randy Holmes-Farley]

I'd be wary as I'm not sure the turbidity of complexed/precipitated K+ in fresh water will be the same as K+ in seawater. The size of the solid particles formed, for example, will impact turbidity.

[sowellj]

I was thinking something along those lines as well. One thing I can try to see if KCl is a reflective standard is just to see if its value appears close to what it is supposed to be on the supplied color gradient. This is kind of self defeating as the whole point was that that color scale is difficult to interpret, but it will at least show if there is an egregious difference.