doseing micro ferts

Hi all
Got my dry ferts through from Aquaessentials and made up some stock solution of
KNO3 and KPO4 but was wondering do you make up a stock solution for
the trace minerals or dose them dry. Tank is 5x2x2 98g, if I mix up a solution how much would I mix with 250ml of water and how much of that do I add to the tank,
if doing a dry mix I will be adding about half a teaspoon three times a week does this sound about right.