Abstract: A tube in one embodiment is formed with a non-stick coating on its inner outer surface. Preferably, the non-stick coating is fluoropolymer. More preferably the fluoropolymer is PTFE. Another non-stick coating is formed on an inner surface of the tube in another embodiment. The non-stick coating served as a de-fouling layer is capable of preventing impurities in the water flowing through the tubes from precipitating thereonto. Hence, the performance of a cooling tower incorporating the tubes can be increased significantly.