Thanks for the inputs. I have a well established tank. Currently my sump only includes the skimmer and some filter pads. Am thinking about getting a new sump that will allow both a refugium and skimmer and would have adjustable baffles for controllable height. Just not sure which is better to have first. Cleaning is a consideration. Seems if refugium is first, then micro fauna would be picked up by skimmer before it gets to return pump. More comments welcome.