I have never noticed that, but yeah that sounds sketchy. (Relevant to your post, if you actually want a water test (in the US), check with your state's coopera

I have never noticed that, but yeah that sounds sketchy. (Relevant to your post, if you actually want a water test (in the US), check with your state's cooperative extension -- they probably offer something unlikely to be associated with salesmen, e.g. Virginia: https://ext.vt.edu/food-health/home-water-quality.html https://ext.vt.edu/food-health/home-water-quality.html )