I have read that Calcium blocks the absorption of Zinc but I find supplements that include both in them. How much does calcium block zinc?

It's not really a complete block, and it's included in many products together due to the fact that both are vital to the body.
I don't really like consuming them together due to the blocking, but I haven't seen the numbers for how much calcium is required to completely block zinc.
I always supplement my zinc in the morning, upon waking.