Fuel cell stack coolant composition

The present invention is a fuel cell stack coolant composition, which maintains the electrical conductivity of coolant low and provides self identification by tint. The coolant composition provides those properties even when a cation or anion exchanger is provided where the coolant is used. The coolant composition includes a base material and a dye which maintains the electrical conductivity of coolant at 10 µ S/cm or lower at 25°C or a dye which can pass through a cation or anion exchanger.