Originally Posted by
Milton Keynes
I used to get bad leg cramps during the summer on long rides until I realized I was washing all the electrolytes out of my system from just drinking water. So I decided to carry some Gatorade powder along with me so I can dump some in one of my water bottles. I put a couple scoops in those portion control baggies like this:

These make it easier to measure out about how much I need.
Plus I make sure I eat a lot of bananas for potassium, and take magnesium supplements for a couple days before a long ride.
Just a 1/4 to a 1/2 cup of that stuff added to a water bottle, on a hot day in the middle of nowhere, can literally save a ride. Doesn't take up much room in a seat bag. And the stuff is dirt cheap and easy to find at any grocery store. A 51 ounce can costs less than 10 bucks, and will last several years.