What's the best mix for antifreeze / coolant - Distilled Water or Tap Water?

What is Distilled Water?

Distillation is nature's way of purifying water. When the sun heats water, this causes evaporation, an example of distillation on the grand scale. Vapor rises from the surface of water, leaving behind all its impurities. These water vapors rise and cool as air temperature in the upper atmosphere drops, and the vapors change from gas to liquid, becoming water, ice or snow. If our atmosphere were not polluted, each drop of rain or snow would be pure H2O.

The production of distilled drinking water is man's attempt to copy nature's form of water purification . As with evaporation in nature, distillation actually removes water (in the form of steam vapor) from the heavier materials that are its impurities. Other types of water treatment attempt to remove contaminants from water, rather than removing water from the contaminants.

In the boiling chamber of the water distiller, tap water is heated to 212 degrees, killing bacteria and viruses. The heat produces steam, which rises, leaving behind inorganic minerals, lead, bacteria, nitrates chemicals and other contaminants in the boiling tank. As the water temperature rises, the light gases boil off and are discharged through the gaseous vent. A stainless steel condenser cools the steam, turning it into distilled water. This water passes from the condenser through an optional post carbon filter, and the purified distilled water that is 99.9 percent pure is collected in a reservoir.

Basically using tap water is bad because it could lead to corrosion of components. Some people might tell you that your tap water is as clean as the distilled you are buying. Tap water obviously varies. Apparantly, supermarket brands of distilled water vary too. The process used does not produce a particularly pure product. Can someone confirm or add to this?

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1989 300CE Astralsilber/Schwarz
1992 300CE Schwarz/Schwarz