The photo is a little old, the refugium now has a big ball of cheato in it and there's a silicone pad under the pump, but you get the idea. The drain is split so that some of the flow goes to the skimmer compartment and some goes to the refugium (on the far right). The drain flow is controled by a ball valve on the skimmer side. The more closed it is, the more flow is directed to the refugium. I shoot for 75% to the skimmer, 25% to the refugium. The blue bin on the right is a recycle bin that I'm using for an auto topoff reservoir, the duct tape and acrylic lid is to reduce evaporation from the reservoir. My ATO rig consists of a double float switch and solonoid setup which controls a Maxijet 400 powerhead in the bottom of the reservoir that send fresh water to the center compartment of the sump through vinyl tubing. The float setup can be obtained from a non-sponsor website, PM me if you want. There's also a TLF reactor running phosban, carbon in a media bag, as well as essential tank maintenance equipment (turkey baster, feeding tongs, mag float, towel, net, etc.).
Edit: Wow, must have just cleaned the skimmer before taking the pic, I can't remember the last time the cup was so clear!