Bleached hair and want to go swimming

Wet your hair with regular water before you go in so it absorbs less pool water.  Try to keep your hair out of the pool as much as possible (wear it up, don't dip your head under if you can help it).  Try a weak vinegar rinse if it starts to go green.  Use 1Tbsp of vinegar in 1 cup of water and pour it over your head (the acid in the solution may help the copper to slide out).  I'm not sure if will work, its just a trick I heard of, so if it doesn't get a shampoo made to get rid of green hair (Malibu 2000 is one, and I think you can probably find other brands for "chlorine removal" at your usual local store.  

The mixture of chlorine in the pool and copper pipes can cause the copper to oxidize and come out into the water, which turns your hair green (its not actually the chlorine itself).   I hear there are chemicals you can add to your pool to neutralize some of the metals before they oxidize....seems like that would be bad for the pipes, but I'm no pool expert so you'll have to do some research on those kinds of things.  

I just wanted to say that I have bleached blonde hair and I went into the hot tub at my sister's apartments. Afterwards we went into the house to make lunch and my sis noticed that my hair was turning green. I jumped in the shower and shampood it for 20 mins. Anyway it took a few days for all the green to come out. So from experience, yes your hair will turn green.  And it's a gross moldy color green too.

I've heard even dumping coca cola over your head works.  That's why I suggested the mild vinegar solution.  Its possible that an acid solution (and maybe even any acid solution, which tomato and coca cola both are) will work.  Its worth a try...just don't use too strong of a solution.  

I use ION's leave-in conditioner for swimmers from Sally Beauty Supply every time I get out of the pool. It helps the air resist porosity. I also use the swimmer's shampoo after I'm done swimming entirely.