fwiw I recently acquired one of these kits. If you buy the "plus" version of the kit you also score a pretty fancy pH meter with automatic temperature compensation, if you don't already own a decent pH meter.
the kit is very compact, probably smaller than a sherrin and contains inside everything you need to test small water samples,including flat bottomed test tubes and a bunch of reagent solids (measured tablet form) and solutions. really neat.
using it did take me back to my early high school chemistry days. you need add 3 drops of this and a drop of that, then a tablet, dissolve, then count the number of drops of a final reagent you add such that the solution changes colour. thats pretty much it except for one test for sulphate which needs you to compare with a neat greyscale chart.
it will give you a result for chloride, sulphate, total alkalinity, total hardness and calcium hardness, from which can be determined by simple calculation the Ca2+, Mg2+ and Na+ ion concentrations.
its quite nifty if you want an idea of where you stand with your brewing water quality, but before you buy one, understand its limitations. Its not very precise but probably well acceptable for what you need for most homebrewing setups. You can discern sulphate only within a 50 ppm range, and the Alkalinity and hardness determinations to within a 10 ppm range.
the other thing to note is that because its reagent based its probably only good for 50 tests or so depending on how much of the reagent you need for the water quality you are testing.
for me, it just really confirmed the quality report that I acquired by local council but for me it also told me what my water filtration system was doing, at least in part and that gives me some peace of mind.
Edited by Goose, 29 August 2016 - 05:42 PM.