To protect hair from chlorine and give it a pre-pool treat, soak it with tap water before a swim, then slather on conditioner or a little oil. Hair saturated with clean water won’t soak up as much chlorinated pool water. Use a swim cap for extra protection, and never leave chlorinated water in your hair. Sea water should be rinsed out too, as salt can cause dryness over time. Use an oil spray to protect hair from its dehydrating effects.