This is a topic of debate for many folks. Here’s my stance on it:
Trace elements are essential and need to be replenished, if your tank seems to be doing fine with water changes, then that method of replace trace elements works for you. Other folks who don’t do water changes as much will often times dose in various methods (triton, Ati, Red Sea). My water changes are slowing down so I am going to see if dosing red sea’s trace elements in accordance to my BRS 2 part and see what happens.
For amino acids- this depends on the nutrient level of your tank. If you have decent NO3 PO4, then likely the effect of aminos will be minimal, IMO. If you have an ULN or struggle with having nutrients, then likely they will have an effect. For me, acropower made a huge difference in my tank and helped return all of my starved corals to their natural beauty, and I dose 20ml’s every 3-4 days in my 100g reef. Adding acropower also increased my alk uptake.
Vitamins- I use seldom occasionally on my fish food for my DT and almost every meal in my QT tank.