eggshell calcium

Mineral, amino acid, and hormonal composition of chicken eggshell powder and the evaluation of its use in human nutrition. - PubMed - NCBI Not sure if this was posted here as I'm on mobile. This gives some of the good reasons to get calcium from eggshells, instead of oysters or other sources...

What is the upper limit of eggshell calcium to take? I dont drink much milk, some days I dont drink any others I can have up to 3 cups... I been taking 2 teaspoons... Would this be good amount? I try to take it with Vit D and some MAG. I think i read that 1teaspoon is 800mg Calcium?.... SO...