HydrX is a concentrated corrosion and algea inhibitor. It's formulation derives from marine engine racing applications where anti-freeze characteristics are not required, but optimum heat transfer and anti-corrosion are primordial. Swiftech HydrX Coolant. For long term protection (3 years), mix (1) bottle to 0.5l (16 oz) of distilled water. For short term protection (1 year), mix (1) bottle to 1l (32 oz) of distilled water.