This is the skimmer I have:
Reef Octopus NWB-150 6" Protein Skimmer
The sump I have came with the set-up and its just an acrylic sump that was converted from bioballs.
In the sump I have the skimmer, return pump, heater, pump for GFO
/ Carbon reactor, and water. Nothing else.
It holds a whopping (4-5) gallons of water with everything in it displacing volume.
I only get about a half of a cup of crap every 2 weeks. I don't know if its because I have a low nasty level, or if its just never been dialed in correctly.
I did add a silencer to the skimmer output when I first got it, but it didn't have a negative effect.