My suggestions would be perpendiculiar to the front of the tank. You'll get more light spreading throughout the tank that way. If you do them parallel you might end up getting "shaded" spots between the socket and the front of the other bulb.
I thought they were supposed to go parallel to the front of the tank. If you had one every two feet (rule of thumb), then I don't think you would get any shading. But you only have 3 covering 8 feet, so you may get some shading.
The height above the would also effect shading. How far above the water are you going to mount them?
Noway Jose!................Just go out and grab a piece of Sun from your local Sun Dealer. You don't need much. A little bit goes a long way........trust me on this one. I got a piece from my local dealer and it burned right through the trunk of my car immediately and created a large crater in the parking lot. Your biggest problem is transporting it to your site and then finding a fixture for it. Have Fun!
