Bristleworms
 

I have at least 30 monster briatleworms in my sump (but not in my display tank). Is this bad? Should I go on a crusade and flush some?

Keep those guys, they're excellent at stirring sand and filling a niche that snails and crabs can't. Keep in mind their numbers are proportional to how much available food there is in the system (like snails in planted tanks).

Great advice!

Lots of people consider them to be a pro addition to a reef tank, but I am not a big fan of them. I have seen them eat detritus and fish poop but at the same time I have been stung by those damn bristle countless times so every chance I got I pull them out of the system. Think of them like mice, if you see one in the open, there is probably a hundred of them hidden in between your wall.
BTW if they are in your sump then that means they are also in your display.