Can low potassium cause leg swelling?

I doubt it, they say eating bananas causes you not to get cramps, but two days ago i had a banana milk shake for breakfast, a banana split later on that day, and a banana for a late snack, and i woke up with an awful leg cramp at around 2:00am, and i don't ever get leg cramps, so i don't know if that answers your question if potassium is a real cure for leg cramps.
yes