Metal Halide - Choices

[plutoniumJoe]

Originally Posted by sphelps

Based on pure numbers 3 250W halides seems more efficient than 2 400W halides. The type of ballasts might change this but really I wouldn't see the gain. Spread is based more on the reflector over the wattage so if you wanted to go with 2 400s you would want reflectors that light up a 3' square well like a lumenarc but then your tank isn't 3 feet wide so it doesn't really make sense. For halides you're probably better sticking with 3 250s, if you want to increase efficiency look into different reflectors as well as bulb and ballast combinations.

What I am reading in the article though states that you get more light for less power out of two 400 vs 3 @ 250.