A middle of the road approach would be starting our with a good trace mix such as the
Nilocg Plantex CMS-B (which is the one I am using). If I want add of something which is absent from this mix (such as Nickel, Na, Fe Gluconate), I just add that to the mix when I am making the 500 ml bottles for my two tanks. Currently a bottle last for 16 weeks. Of course, If you want that full control over the ingredients and ratios, as you would need to do a clone, there is no other way than buying and mixing everything yourself.
Cheers,
Michael