I'm going to take a guess that you added a bottle of Tigriopus californicus ("tigger" pods) to the setup. This species should be considered a "direct feed" item as they don't reproduce well at tropical temps. In warm water, an inordinate number of males are produced, and they will eventually simply all die off or be eaten.
If you want a copepod that reproduces well at warmer temps, look into getting Tisbe copepods (Zoo 2 and AlgaGen have them). They aren't the big, pretty swimming red pods like Tigriopus, but they do reproduce well in tropical setups. Another thing you'll want to do is feed them a good live phytoplankton product such as Phyto 2 or Reef Nutrition. Both are WAY better than DT's.
Another helpful thing would be to get ahold of a ball of Chaetomorpha, as the stuff is the best "pod harbor" out there.
HTH