A copper test really only needs to be done in the beginning when you first set up your tank, to find out if your rocks, sand or water are contaminated (and then, only if you get your rocks and sand from someone else's tank).
You will only need to test for those other things if you are using additives to increase them. Most people don't, because salt mixes contain a balance of those elements, so as long as you're doing water changes, those trace elements should be in the right concentration in your tank.
Those test kits aren't really necessary for the functioning of a basic tank.