The loop is sealed, the tubing is bent, the fittings are torqued. The only component you will touch again is the fluid. Coolant choice determines how long the loop stays clean, how often you drain it, and whether dye settles into your acrylic distro plate.
Start with the base: deionized water with a quality biocide and corrosion inhibitor. It has the best thermal conductivity and the lowest viscosity of any option, and it is what we use to leak-test every build before it ships. Premixed fluids from reputable manufacturers are the same chemistry, pre-dosed, with a dye added. They are the safer choice for most owners because the dosing is already correct.
The Base Fluid
What to avoid: opaque fluids with suspended particles settle in low-flow areas — inside distro plate channels and radiator micro-fins — and are notoriously difficult to flush out. Sugar-based “glow” coolants leave residue on acrylic that no amount of cleaning fully removes. If you want color, use a transparent dye and accept that it will need refreshing.
Maintenance is simple: drain and refill every 12 months, and check coolant temperature during a stress test. A loop that runs cool and clean is a loop you can forget about — which is exactly the point of building it properly the first time.
SIGNED BY THE HANDS THAT BUILT IT
CGP Team