What type of coolant should I use with the PipeWorx 400 cooler?

You must use low-conductivity coolant 043810 — do not use a conductive coolant. Coolant 043810 provides freeze protection down to -37°F (-38°C) and resists algae growth. Using any coolant other than the recommended type voids the warranty on all parts in contact with the coolant, including the pump and radiator. (Page 12)