I don’t think it’s necessary if your fish are fat and healthy. I feed very very heavily for my SPS and feed a lot of fresh and frozen food.Thank you, kenchilada! Any reason you don't add to the feedings for the DT? I've read it does temporarily cloud the water.
If I had a smaller tank I would use vitamins more. I also use vitamins if I ever see a fish developing HLLE.
This is all anecdotal of course.