What "liquid! should I use?

[NitrO]

Hi everyone!!

I`m new in Water Cooling, so I`ll be asking you a lot of stuff in a near future

My first question to you Water Cooling Guru`s is:

What liquid should I use in my system??

XP1900 with Swiftech MCW462 w/Bronx Fittings
GF4 Ti 4600 with MCW40 w/Bronx Fittings
Cooper Radiator
Sicce Idra Water Pump: http://www.sicce.com/pdf_sicce/pompe/idra.pdf

Someones say that pure H2O is the best option, other that 75% pure H2O and 25% Antifreeze, I just don`t know...

Best Regards