attn light gurus
 

Hey
I have recently purchased 2 MH ballasts and DE fixtures... and am starting my hood. My question is which way do I mount the fixtures? parallel or purpendicular to the tanks long edge. it will be a 48" by 16" hood.
TIA
Dano

Perpendicular....

furtherrmore;
How far from the outside edges should I place them

Every DE fixture ive seen has the light parallel to the front of the tank.

I guess if you want to know for sure what is the best way to hang them is to call PFO or Sunlight Supply or you can post the question on Reef Central both are sponsors over there, I always thought you would get more spread by mounting them perpendicular as the light comes out the side of the bulb.

Agreed...

You can go to this link to check out the light distribution for DE pendants. It would suggest that mounting DE pendants in parallel is best. The charts show the output of light under the reflectors with the length of the lamp being on the Y axis. "A right hand coordinate system was used to designate the points on the grid, with the longitudinal axis of the lamp defining the Y-axis" - Part I.

http://www.advancedaquarist.com/issu...03/feature.htm

So you can see that placing the reflectors/lamp lengthwise in parallel would be my choice.

you have a 4X2 tank and two pendents, it doesn't matter weather you make them one way or another but I will vote for parallel.

Steve