Marsha
New member
I went to my LFS and went through about 4 tanks to see the different ways that closed loop and overflow tanks are set up. My new 125 gallon tank has 3 holes in the center overflow and 3 in the display. I am thinking Herbie set up in the overflow with the return in one of the 3/4 inch holes, the other for the drain and the third hole (1 inch) the emergency drain. It was recommended that the closed loop be two drains and the third hole for the return (all 3/4 inch). I know that most people are moving away from the closed loop but since I have never done it before I would like to try it to have fewer things hanging in the display. The sump holds approximately 65 gallons.