Quote Originally Posted by choycontreras View Post
Point of argument:

Mineral water does contain minerals but it is without the scale-causing Calcium and Magnesium ions (which when combined with metals, form oxides or salts). Mineral water processed in the shops pass thru the - water 'softening' stage. Have majored in Chemistry so I believe this is how it goes.

Practical explanation - you dont see scaling in your 'mineral' water containers, do you?
Tap water used in containers do have a lot of these scale causing minerals, thus creating chalky residue on top.

Your arguement is good only in paper. However, you won't distincly see scaling in clear plastic bottles since it won't stick to plastic due to absence of ionic charge. While metals do have a charge. Only way to verify their presence/absence is to boil the water. If there is no chalky residue at bottom of vessel after you pour out the hot water, then there's no Ca/ Mg.

Chaulky residue on containers of tap might be other impurities, since Ca/Mg do not have exclusive affinity to surface tension. And if it does, they won't be visible in bottles since they are filled to the rims.

Distillation burns off all remaining Ca/Mg

You might have a major in Chemistry but I'm a genius