[Delphinus]

Congratulations, your tank is well under way. :D Sounds like your 'pods are forming larger populations. Could be copepods, decapods, isopods (sp?), or even juvenile versions of those.

What will happen, is, basically, you will get population explosions of these little guys as your tank matures. Basically what's happened is, some eggs have hatched, the first generation laid eggs, those eggs hatched ... and so on. Eventually, the populations will crest somewhat and the numbers will maintain at a more steady sustainable number.