HQI's Parallel or Perpendicular??

[Shroom King]

Planning my 90G lighting using 2 - 250 HQI pendants...

The pendants seem to hang better perpendicular because of the power cord coming out one end. I know I have seen them hung perpendicular before, and thought I saw a thread once stating this was even better as well, but I can't find it now.

Is it better to have them aligned parallel or perpendicular to the tank??

 

[Aquaduck]

It depends on the reflector. Hold your lights a few inches above the floor and see which way the light spreads. The shape of the light cast onto the floor should be rectangular or square. Position the pendant so the shape of the light casting matches the shape of the tank.

 

[Shroom King]

That makes perfect sense Aquaduck. I will do that. Thanks!