Trace elements are used to aid photosynthetic and enzymatic reaction within the confines of a marine aquarium. They can be administered through feeding, water changes and liquid supplements.
You don’t want to overdose trace elements! The best way for you to replenish trace elements, that become depleted through fish respiration, adsorption and absorption by chemical media and even from certain materials used in your tank like glass and hosing and growth of livestock, is to do weekly water changes. This takes the guess work out of administering trace supplements and possibly overdosing.
If you feel better dosing, just follow the directions on the bottle and dose a little less than recommended to be safe.