The trace elements may be useful. Some certainly will be if you are not dosing any. The only concern is if some are already on the high side, but I'm not sure how much the Seachem product will make such a scenario worse.
Just realized this is Seachem's 'Marine Trace' which is a different product than their 'Reef Trace'. Marine Trace is for marine fish which I'm not quite sure why since we don't typically think of trace elements for fish. Good healthy variety of foods soaked in an occasional vit-chem should be good enough. I bought it to try a new coral trace element product. Guess I'll have to burn through this before heading back to the coral Reef Trace elements.