A catastrophic tank crash turned me off on the hobby a few years back. We were building a house and part of the design was a "fish room" down in the basement. After losing everything I had just moved the equipment down and let it sit....for 2 years.... I am rejuvenated and ready to get my display setup again. I am looking for some guidance on the plumbing as I am trying something new. I am looking to use the Herbie method for the overflow, I have dual overflow boxes on a 150 gallon, 6 foot tank. The sump will not be directly underneath the display though, it will be off to the side so I can access equipment easier. (The entire setup would look L-shaped on a floor plan.) My question is this, should I: 1) Do a dual herbie method, with the return running up the back side of the tank? There would be elbows in the drain lines since the sump is off to the side. 2) Do a single herbie method with one overflow box and run the return back in the 2nd overflow box? If I did this, what would I use the 4th drilled hole for? (1st overflow box #1 hole for siphon drain #2 hole for emergency; 2nd overflow box #3 hole for return, what is #4?) I am also planning to T the return for flow into the refugium section of the sump. Any guidance would be greatly appreciated!