skimmer/refugium placement

Here's a thought to discuss....In a sump system, is it better to place the skimmer before or after the refugium. After.. to "clean (if you will)" the water flowing out of the refug and DT or Before to let "clean" water flow through the refug?



I came up with this thought after seeing the refug getting kinda "dirty", IE: glass sides being covered, as in the stuff you would be cleaning off the DT glass. Thinking this water is going straight back into the DT and not filtered until it returns to the skimmer.



Thoughts?