These are great comments above and provoked some questions:
I inherited a tank with a couple different kinds of pods. I have no idea which. My sump / refugium / and DT are crawling with very tiny pods all over the glass at night. There are some bigger guys in the rocks/macro algae. The question is whether I need to do anything more to sustain this. I don't dose phyto because where I live overseas, phyto is no where to be found. Will the pod population continue to survive on its own? Will they eat up any existing plankton types in tank and then crash? Or do they just eat algae? Should I order in via mail some phyto/zoo plankton?