Ive seen a dramatic increase in my amphipod population (Gammarus) since starting to feed them. I use pellet food. They love anything they can cling to, be it a sponge or chaeto.
I personally wonder if copepod cultures, like parvocalanus, might be best kept separate given the amount of phyto it seems to take to raise them. Not sure they cling to anything, but are more pelagic.
Tisbe, to me, seem to love micro algae covered glass and may not need as much phyto, if any, with such hospitable substrate - perhaps more demersal.
$0.02