Sump Plumbing

[Zylumn]

Like a good skimmer the longer your sump/ref has contact time with the water the more junk it will extract from the water. With your design I would put a single baffle next to your refugium line so when water comes into your sump it would then flow even over the baffle along the length of the tank into the refugium. Place your line coming down to the skimmer as close to the skimmer intake as you can with preferably the skimmer intake between the 1" sump line and the return pump baffles.
Good Luck it looks like your on the right track.
Kevin