I have the kind of hair that the sun and even the minerals in tap water will leach even the natural colors so I just bought some shampoo for colored treated hair by Tresemme. It works great. It seals the cuticle keeping it from frizzing.
I've been thinking it might work on your kids swimmer hair or maybe just some swimmers shampoo even which will take the minerals and chemicals out of the hair from the pool water.
This swimmers shampoo gets good reviews. I've thought about trying that before I bought the other.
http://www.aubrey-organics.com/Produ...?productid=071