EK-Quantum Reflection PC-O11D Mini D5 PWM D-RGB User Manual page 2

Before you start using this product please follow these basic guidelines:
Please carefully read the manual before beginning with the
installation process!
The EK Fittings require only a small amount of force to screw
them firmly in place since the liquid seal is ensured by the
rubber O-ring gaskets.
The use of quality market-proven corrosion-inhibiting coolants
is always strongly recommended for any liquid cooling system.
Do not use pure distilled water as a cooling liquid! For best
results, EK recommends the use of EK-CryoFuel Coolants.