Vitamin and Pouch Question

 I am supposed to take a 1200 mg supplemental calcium tablet or Viactiv chewable.  I bought the Viactiv.  How many of those chewables am I supposed to take?  The way it's written on the paperwork, it sounds like one?  The container says 500 mg calcium though?  I'm not sure if I am reading too much into this.  

Ok, so, I am trying to figure out how fast the pouch emptys.  If your pouch can only hold 1 cup and I am sipping all day, how do I know if i have exceeded the 1 cup in my pouch?