Adding calcium to orchids

[Kailyn]

hello all
I am wondering about ways to add calcium to your watering/fertilizing regime. most of what I read advises you to buy a fertilizer already containing calcium but I can't seem to find any and am not inclined to buy anymore types of fertilizer to try at the moment as I have at least 3 different kinds floating around under my sink... would crushed up human calcium supplement do anything? I've read about eggs shells but it seems pretty split opinions on if they work or not. One website said diluted milk but that seems like a rot invitation to me....suggestions?