Water has a unique combination of physical, thermal and chemical properties that makes it ideal for use in PC water-cooling systems. However, to help minimize the negative effects of corrosion and prevent the growth of microorganisms, it is necessary to use coolant additives.

Welcome back to the second part of our article on PC water coolant chemistry! If you have not already done so, please check out Part I for detailed information on some of water's unique physical, thermal and chemical properties and the various types of water available for use in PC water-cooling systems.

In Part I, we discussed some of water's unique properties (thermal conductivity, specific heat, viscosity, etc.) that make it an excellent coolant for use in water-cooled PCs. We looked at several different types of water (tap, distilled, bottled, DI) and concluded that distilled water or purified drinking water were two potentially good sources of water that were easily obtainable.

We also noted that most anything you add to water (antifreeze, corrosion inhibitors, windshield wiper fluid, etc.) will decrease water's overall thermal properties. So why not just use pure water as a coolant? That question brings us to Part II.

Pure water might initially appear to be an excellent coolant for use in PC water-cooling systems. Unfortunately pure water also has a few undesirable properties. These include:

• Pure water is corrosive to metals due to the very low dissolved solids content (ions)
• Water promotes oxidation of metals also known as corrosion
• Water typically contains small quantities of various microorganisms, which may grow and multiply over time

• Too Pure?
• General and Galvanic Corrosion
• Water Additives (surfactants, corrosion inhibitors, antifreeze, biocides, etc.)
• Maintenance
• Basic Coolant Mixtures
• Conclusions