Metal Halide Placement Question

I have a 5 foot tank and i just bought 2 250w sunlight supply metal halide pendants and i wanted to know how far in i should put them from the sides of the tank. I was thinking like 12" in from each side is where the start of the pendants should be but i have no idea. My center brace is glass so the shadow of a normal center brace wont be a problem. The Pendants are 11in long.
Thanks

 

normally a halide covers 2' by 2'..so maybe that can help you eliminate shady spots,,

 

Ok so that would make it 1ft on each side right? because its a double ended hqi.

 

I make it 6 inches in from each side

the area covered being 2 x 2ft - thus 4ft and you have a 5ft tank

Steve

 

This statement is misleading. The light can cover more or less than this depending on the following factors; distance off of water and reflector type. Hook it up, hold it above water, and see where it covers half of the tank...then hang the other the same distance. Or you can divide 60" by 3, and space the lights at 20" on center to give you identical coverage.

 

Right now its looking like ill be hanging them 10" off the water. What i have right now there isnt much light in the middle and i want to get it brighter so i was thinking maybe 10-12in off the sides which i think would give me enough light spread. I would think that with it 6in off the edge wouldn't a good amount of light basically be wasted? I forgot to mentions they will be mounted in a canopy.

 

I meant the shade or refletor position ending about 6 inches from the edge
not the lamp itself

sorry for that

Steve