As long as I'm ranting on here (and I do apologize for having seemingly run everyone off of this important thread).:
I'm going to rant about those ads I keep seeing for a particular home water filter system.
These filters likely contain some mixed-bed ion-exchange resin so that the filter demineralizes (deionizes) the water. Thus, when, in their advertisement, they read the water with their cheesy conductivity meter, it reads zero conductivity (high resistance), indicating low dissolved solids in the water.
But the thing is: Drinking deionized water may actually be bad for you! It turns out that the body may need some mineral content in drinking water for best health.
A study by the World Health Organization (WHO) showed some potential issues.
Since RO, distillation, and other microfiltration methods are often employed when dealing with catastrophic events or in underprivileged areas to get safe water to those affected, and desalination is becoming more common to supply drinking water for areas with no access to fresh water, the question naturally needed to be studied.
https://www.who.int/water_sanitation_health/dwq/nutrientschap12.pdf
Normal minerals found in drinking water are not harmful, and in fact are good for you or even required in reasonable concentrations.
It annoys me when I see these smug commercials selling a product whose results are not only unnecessary, but potentially unhealthy.
We had deionized water on tap at all of our laboratories because it was necessary for preparation of samples and reagents for various analyses. And despite this water being "ultrapure" from the standpoint of ionic content, it always smelled of algae and tested to be microbiologically unsafe. The Bacteriological departments of the labs could
not use this "ultrapure" water directly for any of
their testing. They had to filter it through 0.45 micron filters at the point of use or boil it, etc. And NOBODY drank it!
Of course your tap water should already be disinfected. And passing it through the deionizing filters hawked in these advertisements would not necessarily contaminate it.
But the zero conductivity reading does not tell you much about the chemical or microbiological safety of the water. It's an almost
useless test for drinking water safety.
You could still have lead, mercury, thallium, radionuclides, bacteria, protozoans, viruses, pesticides, etc., in concentrations above their MCLs (maximum contaminant levels) and still see relatively low conductivity.
If a three dollar Chinese conductivity meter could detect dangerous contaminants at their MCLs, people wouldn't pay laboratories to use their ICP Mass Specs, gold trap mercury fluorescence machines, bacteria incubation tests, GC Mass Specs, liquid chromatographs, etc., to give them court-defensible analytical results!
I really hate to see bogus science used to dupe uninformed consumers. It's snake oil of the worst kind because the product is not only unnecessary, but potentially harmful.
