What Is The Best Water Testing Kit?

[andywg]

Accuracy will never be an opinion. It will be an absolute. Either the test is accurate, or it is x% high or low.

Many people on here claim tests are accurate, yet I will wager almost none have had their water tested by a calibrated professional meter. I know one person did and they found that nitrates of 80ppm on the test were 27ppm on that of the water board tester whilst their ammonia reading of 1ppm was actually 0 (to 2 decimal places).

 

[TigerIssey]

Any test that relies on colour interpretation is going to be inaccurate and will vary according to the experience of the user unless you use a spectrophotometer calibrated to the correct wavelength to read it. Having worked in microbiology laboratories for 11 yrs, all these tests are is what we would call screening or point of care testing. Don't get hung up on numbers, as long as you use the same test kit every time and get to know your readings over periods of time, they are as accurate as they need to be.
We could all do the nitrate test from the API master test kit on the same water sample and all get different results, it will depend on the user. Just use as a guide, that is all they are meant to do.