^ What he said. Your salt mix already contains it, and one little shrimp is not going to deplete that. If you keep doing water changes, you automatically replenish it (and boron, selenium, and a laundry list of other useful elements.) Don't ever let anybody sell you an additive without selling you a test specifically for it, so you can be sure you're not overdosing: the short version is---don't dose what you don't own a test for. Just as you can overdose yourself on vitamin/mineral pills, all the way to toxicity [they become poisonous]---you can overdose a tank on supplements.