My DD swims with the school (she's 10 yo and has waist-length hair)
It's making her hair so matted 
I'm already doing:
a plait for school
she wears a swimming hat and rolls her hair up
conditioner to comb (tonight I used Ojon -in the tub, you melt it and rub it on)
a Tangle Teaser ( we've had it a few years, I think it's gone 'soft')
a wide tooth comb
a showerbrush
a paddle brush
Tonight was a nightmare her hair was like felt it was so matted (TBH I hadn't brushed it as much as I should over the half term- I injured my arm)
I need something to apply at night then rinse out after swimming (so not oil or anything that will make her leave an oil slick in the pool).
And when we go on holiday she'll be in the water every day.
Is Phillip Kingsley swimcap worth a try?
Or anything by Paul Mitchell out there?
I'd give most things a try, to avoid the ordeal we've just been through- ouch 