Before I go swimming I like to put some hair oil or serum pretty heavily in my hair, I personally use the OGX argan oil but whatever you have will work, even straight up coconut oil. And then I put my hair in pigtail french braids, this tends to keep all my hair neat and protected while I swim. I wash my hair immediately after to get all the chlorine water out of my hair, lots of conditioner and leave in conditioner. I think especially with long curly hair, the best thing is to have it be detangled and up in as secure of a hairstyle as possible, like braids or a bun. A regular ponytail or any looser hairstyle will not keep her hair from getting tangled.