[Dix Dogfight]

_Mike_
I'm afraid BB2k is right in this matter. The more water you add the longer it will take for the system to reach its equilibrium = stable working temperature. One gallon of water takes approximatley 200 seconds to heat one degree kelvin/celsius with a 80W heat source. So if the temp difference between start and stable temp is 20 degrees. Then the time it takes for the system to reach stable temp is 20*200=4000seconds=1h7min.
If you make the total volume of water 5 gallons,as you propose, the time it will take to reach equilibrium will be 5*4000sec=20000sec=5h33min.

Now do you really think |PuNiSh3R| would want to wait 5h to see if his system is stable?

I run my system with approx 0.25 gallon of water, and it works no problemo. However that is only a normal wc-system but the difference between my rad loosing the heat and |PuNiSh3R|'s phase change doing the job is indifferent.

As for using 50/50 glycol/water. I think you want to have as little glycol as possible=needed in your system. Due to glycol's bad thermal properties.
The water won't be -40degrees celcius when you run the computer. So no need for a lot of glycol.