Copepods and Sea Urchin

[Baby Ray]

Hey everyone,
I have a 20 gallon sump and I put a long spine sea urchin in there to keep the algae growth down. Lately I have had a huge outburst in copepods. I know that copepods eat detritus so should I leave all the sea urchin poop in the sump for them to eat or should I siphon it out?

Thanks

 

[Baby Ray]

Just did some research and I think what I have might be isopods instead of copepods. What exactly do they eat?