I wanted to do a write up here because there is not much info for it on this site. The overflow is named for the user that posted it on Reef Central. It was back in 2004, and plenty of people use this system with no problems. The point of it is zero noise, and zero bubbles. This is for drilled tanks. Here is the original thread. All 600+ posts for your reading pleasure. His very first post explains it quite well and I see no reason to repeat it. http://www.reefcentral.com/forums/showthread.php?s=&threadid=344892 The point is this, keep your main drain below the water level in the overflow box to keep out air. Use the gate valve to regulate this level. Use what was your return line as a secondary drain. Run it straight to the sump with no restriction. The secondary drain sits up higher above the water level, but obviously below the highest point you want your tank level. You plumb your return flow over the back of the tank. Without further ado.... I added a fuge to my setup, and wanted a bit more flow to feed it. I split my drain line to do this. Here is my setup. I had barbed bulkhead fitting with vinyl tubing. Very restrictive. I wanted to go to threaded fittings and oversized PVC. Here is a pic of the difference between barbed and threaded. Drain Return I went with 1" PVC for the return and 1.5" for the drain. If I had to do it all over, 1.25 is plenty. Here is how I connected it up. The drain uses a simple 1.25 flex PVC coupling from HD. The return just uses one made from 1.25 vinyl tubing. I had to use some silicone on the threads to ensure a seal. Since both are now returns and not subject to pressure, it is more than adequate. I have tons of flow now from the upgrade. However, I now had tons of noise and TONS of bubble. I mean a metric **** ton. A lot. Enter Herbie.