I agree with the other posts.
When I was buying a peppermint shrimp for my tank, Live Aquaria had said that it's best to supplement with iodine to help with the molting. After asking the staff at Scales, they said that as long as you do regular water changes, you'll be fine (i.e., that's why salt costs what it costs, it's loaded with trace elements).
Save your money and stick with your water changes.
--Mike