A final yet important consideration to make is liquid coolant type. Theoretically, you could fill your water cooling system with anything, but some fluids work much better than others. First of all, do not use tap water. Tap water has minerals, bacteria, and algae in it which will corrode and cloud your water cooling system, possibly causing a catastrophic failure.
Another alternative is de-ionized water. De-ionized or non-conductive water may seem desirable initially, because it is a poor electrical conductor, and therefore will not cause much damage if a leak occurs. However, water is an excellent solvent, and so if de-ionized water is put into a water cooling system, it will corrode the water blocks to get its ions back.
Therefore, de-ionized water is not something we recommend, either.
A good choice is distilled water, because it is relatively cheap yet pure enough to use in a water cooling system. Distilled water will not deposit harmful minerals in your system, nor will it cause algal blooms because there are no living organisms present.
It will not, however, corrode your water blocks because it is not de-ionized. There are various additives which may be added to the coolant in your system.
