The best way to keep Nitrates low is to keep biological filtration at a minimum. A good size skimmer along with live sand and live rock will remove organics before they have the chance to be broken down into Nitrites... Nitrates. Water changes compliment this when needed, but are more importantly used to replace trace elements & buffering compounds.
I have never used a refugium. However, I have personally talked with a number of hobbyists who liked the results.