Questions about dry ferts

I'm not really sure if this is the right section to post this so forgive me guys if this is out of place...My questions is that I'm using dry ferts and I'm not sure where to find some info in mixing the micro nutrients(trace). I bought a dry chelated trace element in my local hydrophonic store and I'm not sure how to mix it with RO water..I have the nutrient calculator but it doesn't have anything for trace...My question really is how many tablespoons of this stuff could I mix in a 500 ml water to make a good mix????..Does this sound dumb guys????I'm sorry if it is....thanks...