Unless you’re doing 100% water changes, you will always have diminishing returns. Let’s say you do a 100% water change or are starting with a new tank, if your tank uses even 1% of the trace elements in your salt mix, if you do a 25% water change, your trace elements are only going to be replenished to 99.25% of their original level, and each water change that isn’t 100% will further diminish those levels. Water changes just aren’t really a good way to maintain/manage trace elements (or alk, or nutrients, lol).Guess it would depend on how often and how much water percentage you change coupled with the mount of corals and fish in the tank. Obviously nano tanks much easier to replenish with water changes.