I'd put the the 1050 in the left rear corner half way down facing the front middle of the tank at the top and put the 1400 in the rear left corner pointing at the same point! imagine a bullseye at the top front middle of your tank and hit that from the rear corners. With the 750 I'd put that in the rear middle top of the tank hitting the same spot, ya may want to point that one towards more middle of the front tank