[rayjay]

Because of the dwarfs preferences are to sit perched and wait for food to pass by close enough for them to snick it up, you have to add a lot more brine nauplii to make sufficient food available for them. There is plenty left for mysid to feast on.
I've always had to remove the uneaten foods before the next live feeding anyway because the food QUICKLY looses its nutrition.
There are a lot of dwarf tanks with mysids in them and I've not heard of any tank not having sufficient food for both, unless an insufficient amount was added in the first place.