4 days post op and when walking yesterday i got some pretty strong calf cramps, i am thinking pottasium deficient

Definitely sounds like it. Since you're only four days post opp you're still on liquids your options are limited ... but, if you can get your hands on a couple of papayas (fresh or frozen) and blend with Water and ice you can have yourself a nice very thin papaya drink that will elevate your potassium.

Unfortunately potassium supplements are known for dropping your potassium before raising it so try to raise it naturally first.

I've been getting calf and foot cramps even since I was banded. Small price to pay, but it sucks! Nothing seems to alleviate them except for "bad" phases when I'm eating more carbs and a more varied diet. Drinking a ton of water helps a little bit. I feel your pain!

Try heat as well, my whole family gets them.

How about drinking a sports drink? Get your electrolytes in balance.

I had a recent bout with c. diff., and was horribly dehydrated. My doctor had me drinking gatorade. He didn't care if it was sugar free or not, he just wanted my electrolytes back where they belonged.