the 180 i bought was supposed to have the stand pipe installed but wasn't. how far below the tank water level should the drain opening be? should it have an elbow on top? a "u"? should it have a "tee" on top so it can have an elbow or "u" and still have an open top for air? pics of your standpipes would be great. since its raining today i figured i would get all the bulkheads installed and maybe the cls spraybar as well. thanks for any help in advance.