Calcium/muscle cramps

Hey ya'll. Lately I have gotten some godawfull cramps in my calves. I mean the kind that completly paralize you. The last one while was paddling and it couldn't have happened at a worst time just before hitting the biggest rapids on this particular river. I had to stop everything and lean forward and strecth my leg as my canoe was headed for this big rock. I recovered enough to get some composure and power my boat to hit the very edge of the drop without flippin'. I would hate to think what it woulda been like if I had flipped and had to swim the rapids while my calf was cramping so as you can see this cramping thing is of much concern to a whitewater paddler like myself and as ole Barney Phife use to say "Let's nip it in the bud Andy"......;+D

I know enough to keep hydrated while paddling and always carry a hydration bladder and sip constantly while on the river. Someone told me that muscle cramps can be cause by calcium deficencies so I'm thinking about using a supplement but first wanted to check out some posible alternatives using whole foods.

My daily routine includes 2 oz of wheatgrass and 24 to 32 oz
of a fresh made juice mix of carrots, celery, beets, parsley
and green apples. Since I'm on a daily exercise/weight training regimen at the moment I supplement with 80 grams of protein. In the evenings I have a great big salad. The base for the salad is leafy greens which almost always include spinach and an assortment of raw veggies and tofu or tabouly or cous-cous. I tought I had my bases covered but now with this cramping I'm thinking I may be lacking calcium.

I always drink at least 1 quart of water during my workouts with 16 oz of apple juice right after. In total I drink 3 quarts of water a day so I think I have my hydration covered. One more thing. I'm also supplementing with 2 tbsp of Flax Oil daily.

I have gonne through a major physical/mental/health transformation in the last 3 months. It all started with a 40 day Master-Cleanse fast followed by Dr. Clarks liver flush. I'm at the tail end of a parasite cleanse and when that's done I'll be doing another liver flush. I'm feeling great and getting stronger and more fit every day. My resting heart rate before my transformation was in the mid to high 70s I just checked it today and it was 52/54 bpm!! woooohooo!!

Given my dietary routines above I would welcome any sugestions from you more experienced dudes and dudettes ;+D
BTW I'm trying to keep to a mostly raw regimen with no dairy. I have read that Hijiki has major Calcium content but in my neck of the woods it is MAJOR expensive.