And on another note, as far as EFA's, I do not like getting too out of balance between 3's and 6's which I why I use Udo Oil in my shakes or as salad dressing with balsamic vinegar and do not use individual Fish Oil or Primrose, Udo has it all in one!
As for Calcium blocking the absorbtion of other minerals, that is true so Trab, make sure to take your Z and M about an hour after the cal, right before bed. Or take a ZMA right before bed, an hour after any calcium.