Question

Why would people on the dive tour require fresh water showes?​

Answer 1

Salt. It can dry on you and your equipment leaving crystals that might not do you much harm (dry skin, uncomfortable itchy feeling) but will definitely start degrading your equipment. But even after diving in fresh water, a good rinse it needed to prevent aquatic organisms growing in the equipment, and definitely after a chlorine treated pool to prevent equipment breakdown. I always rinse my ears whatever type of water I have been diving in - a damp warm environment can encourage all types of infection.