I was under the impression that cramps are from an imbalance of potassium, calcium and magnesium. Supplementing the one you are lacking generally resolves the problem, but its hard to know for an individual without trial and error unless you are 100% sure of your diet.

I mentioned in passing to a nurse at my gym that I get calf cramps from running. She told me to get a supplement from Amazon called Calm. It eliminated the cramps, and after an especially rough squat workout I used to get cramps, it also took care of that. Although you need to be very careful with the dosage, it is basically a laxative.