Actually, you don't need special shampoo for that.
Just make sure you wet your hair thoroughly with fresh water, and even better, then put some conditioner in your wet hair before getting in.
The fresh water saturates the hair, so it won't want to soak up the chlorine, and the conditioner creates a barrier.
Bonus tip - Hair conditioner works better than any shave cream when shaving your legs. I imagine it would work well on the face too.
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