[Cova]

1-Distilled Water
2-Tygon lab-grade, 3/8" ID thin-wall
3-Water-wetter. Initially ~3% WW, after about a week the coolant was clear again, so I added pure WW till it returned to the same shade of pink it originally was.
4-None.
5-During normal operation - None. At LAN parties/occasional showing off (less than 1% total operational time probably), 1 blue neon and some blue LED's)
6-~1 Year.
7-It is now a milky pink. I am unsure if it is the coolant or if it is a white buildup on the tubing.
8-All copper parts with brass barbs (Edit: block is soldered shut - depending how much leaked inside there could be a very small, or reasonably large surface-area exposed to coolant - is a Maze-2)
9-Possible thin white buildup on tubing (see #7).