I built a standpipe for my overflow that just uses10,9,8,and 7. It works perfectly quiet. It fit right on what that picture would call 6, as there was already pipe there designed to have a foam filter fit over it. Also, unlike that guys' findings... I didn't have to oversize the standpipe. I used straight 1" all the way through. In fact... its probably even smaller because I used sch40. Still, no issues though.