sump design questions


New member
I have been working on drawing up a sump design using google sketchup. A friend has a CNC machine and is going to build it with me. I am basically going with a Model F design from I just lengthened it a bit. So the teeth on the divider between the refugium section and the center section, how wide should the teeth be? I currently have them drawn as 1/4" wide spaces and 1/4" wide teeth. Is that good?

Also I was thinking an external return pump because I am going to need a pretty big pump and don't want to add that heat to the system. Big pump because it needs to overcome a story of head pressure. Also we have a Chiller so I need to loop that off the sump. So I was thinking bulk heads. Obviously the return line bulkhead in the center section. Just not sure how to run the chiller loop. Intake and return all in the center section, maybe on opposite sides. Or should I intake in the left section with the skimmer or would I risk bubbles doing that bypassing the bubble trap? Any thoughts? I guess I am thinking all bulkheads in the center section to avoid bubbles but would like some feedback. Any insights would be appreciated.

Thank you,