On my lunch break here, I was just going over the 180 Starphire thread, and realized there was mention of using a sump with an add-on overflow, and that I do not have that represented in the schematic.

1. Is this a sealed sump to prevent CO2 escape?
   1. If so, is this a commercially available sump? If so, what is the make and model?
   2. If not, is this d.i.y., or just (heavily) modified commercial model?
   3. (I am looking to get an image so I can draw it at some point.)
   4. (How does one seal a sump anyway and have air/oxygen for the bio media?)
2. Is there a separate pump for the return?
   1. If so, what is the make and model?
   2. Where and how is the water returned to the tank?

No rush... :-)