Louey,
the 1400gph is good, in "close ups of tank 004.jpg" page two of this thread, you show the top of the glass in one of your wier boxes, what is the length of the box ( front and two Sides )( which you have two boxes) in inches.
are the bottom of the slots level with the glass of the weir...
Louey,
love the tank, a question for you, how much water are you pushing over your weirs?, what length are the weirs?, what is the depth of water on top the weir glass?, ok it was three questions really.
Regards
Steve