Here’s my advice:

Before the pool, rinse the hair with fresh water (shampoo will strip the natural oils and styling product that can add extra protection), make sure the whole head of hair is completely, soaking wet.

Next, work a heavy conditioner through the hair from the scalp to the porous ends.

Next, tie long hair up into a bun or pony tail (loosely so that you do not overstretch the hair and cause breakage) and cover with a heavy swimming cap like the granny caps or a silicone cap (the latex caps are too flimsy and can break with the lightest of tugs).

After swimming, make sure to use a shampoo with stripping properties (unless you have colored hair) like baby shampoo (if you have colored hair, then only use color protecting shampoo) or chlorine removing specialty shampoos. Shampoo TWICE (once will clean the strand and the second with clean the scalp) and condition scalp to end.

Rinse thoroughly and comb carefully with a wide tooth comb or pick.

Even after I began to get low lights and highlights, this routine allowed me to swim competitively without looking like I lived at the pool, even though I did.

Cheers!