Been busy and just getting around to answering.
I drink lots of orange juice and try to take a multi regularly when training. Cramping isn't necessarily from potasium defeciency. Could be moderate dehydration, low calcium, or just an imbalance in the mineral profile in your body.
My suggestion is to take a high quality multi vitamin, eat fresh fruits and veg as much as possible(oranges/juice are great) and make sure you are drinking shit tons of water.
Cheers,
Scotsman