I like the link posted a couple days ago about movable baffles, i will for sure be doing that on my next tank. You have a very common setup, the only fall back is that you're skimming out nutrients that your refugium could use. But, it is a very common setup, and will still work out great if you are unable to split your drain.
I went with this setup:
http://www.melevsreef.com/acrylics/sumps/f/sump_f.html