Need advice on a sump...please?

[2quills]

Hi,
I am a new saltwater aquarium owner, I purchased a 2 year old 125G tank from an add off of craigslist. The tank is in good shape. Right now it is primarily fish only with a small handfull of crabs and snails. Ultimately I would like to turn it into a beautiful reef tank. One of the first things I am going to need to do is upgrage the filtration. Currently all I have on there is what the tank came with which is a Rena XP4 cannister filter. I've been doing some studying on the subject and have decided that a sump with refugium would ultimately be the way to go. Would anyone object to that? I've read that wet/dry filtration is better for fish only instead of reef. I'd like to keep it as natural ass possible. The tank already has approximately 175-200lbs of LR and about a 1' inch sand bed. I've come up with a rough design of what I am hoping to do and I was wondering if any of you reef keepers out there could offer me some input on the subject.
Thanks in advance,
Quills
Here's a pic of what I was thinking for my sump...

 

[acrylic51]

You might have issues with your skimmer being consistent as far as skimming with your "drain" line dumping into that compartment. It's good your looking to feed your skimmer the dirtiest water possible though.

 

[gill again68]

Not sure how you plan to regulate the flow in your fuge? You may want to check melves reef.com. He has sump designs that are proven and address potential issues.