If you've ever swum in a synchro competition, there is one thing you know: Gel is beast to get out of your hair once all is said and done. I've known swimmers who were still trying to separate their hair from the concoction a week later.
Granted, I'm pretty new to the synchro thing, but I have had the experience of gelling my hair. Fortunately, I've also had the benefit of 40+ years of experience in my teammates who've all been there, done that.
The trick I've learned to removing gel from hair is to use conditioner. Simple, huh? When you're ready to de-gel, just coat your gelled hair while it's still in the bun with a thick layer of conditioner then hop in the shower. Make sure you pay attention to those tricky areas around your ears and along your nape where gel likes to hide out.
While you're getting the chlorine off your body, the conditioner softens the gel. Rinse it away with hot water. Shampoo and condition your hair normally. You'll be good as new!
I've also found that conditioner is like the be all, end all of de-gelling. I got a dob of gel on my tech suit at nationals. Back at the hotel, I smeared conditioner on the spot and let it set for about fifteen minutes. It rinsed completely away. No problems.
I love conditioner! I use Infusium and have not yet tested it against other brands. If it ain't broke, why fix it?
I've also heard that pineapple juice is really good for de-gelling. I'll let someone else run that experiment.