Hi Charles...and welcome to the
Talking Reef! First off, you're doing the 'right thing'. By posting the questions you have, in a forum like this, gives you good, practical information and also helps others who may have the same questions!
I'm glad that you found the Boston Reefers Society helpful. They were the catalyst for my habit (read "hobby"). Make sure you introduce yourself to me at a future meeting. I've been a proud, card carrying member for a while now. I'd be nowhere without them.
In most
sump with
refugium setups, folks opt to split the overflow water source and direct it into both a
skimmer section and, simultaneously, a
refugium of sorts. You can do this with various T and Y connections, in either
PVC or fleixible hose. The flow of water through the chambers is controlled with a ball valve or similar union placed between the output of either side. I opt to put that valve on the side closest to the overflow and work with gravity.
You DO want overflow water to be skimmed. It should be skimmed away from or before the
refugium and its output to ensure fewer casualties in planktons and micro crustaceans that could feed your system. The ratio of water to
skimmer -vs-
refugium is really dependant upon your system. What I mean is that some folks opt to have more flow to
refugiums, depending on the "purpose" of the
refugium, while others would rather keep lower flow etc. in a
refugium and push the majority of water to the
skimmer. In either case, get a good
skimmer 
Your best bet is to branch off the overflow to two, opposite ends of the
sump. On one side, set a footprint for your
skimmer and have some baffles from that chamber, working towards the center of the
sump. On the opposite side, set another chamber with tallish divider for your rerugium. That water will cascade over the wall toward the center as well. In the center, you can run the
sump lower, and set your return pump. If any of this doesn't "visualize" as you are reading, I can send some pics, or a diagram. Right now, I'm on the family
PC and don't have any of that handy.
I'd cut that canister out, and set up the
sump again...just as you planned. I'm in the midst of a
sump project myself and would love to help you with yours. I'm in Marlboro, not TOO far away. If you'd ever like to meet and see my tanks,
sumps etc. let me know.
Feel free to
PM me here, or on BRS if you want to go into further detail.
Ciao for now!
Dave
