Distilled water, no direct sunlight on the loop, avoid tight bends in the loop. Double-check your connections before firing it up and let it leak test for a while before you power on the system for good. Distilled water should be non-conductive, as it's usually the minerals in the water that make it conduct electricity. Most spills can be cleaned up and dried off without ruing hardware. There was one time I bought a used Danger Den block that had the O-rings go bad on them. It ended up dripping distilled water mixed with antifreeze on the back of my video card (IIRC Radeon 1900XTX AGP) and into the AGP slot. The system was running fine until the BIOS died on the DFI mobo (common issue in the NF2 days). I got the BIOS replaced and she was up and running again.