metal halide lighting

[caffeine]

How well does the light from a metal halide bulb spread out? With a fluorescent hood the light is spread evenly horizontally giving plants an equal share of the light, but how well would a single MH bulb work? It seems to me that the light would be concentrated in the center and the plants on the outer areas of the tank wouldn't get enough light. Would it be worth it to use 2 lower powered MH bulbs or a single high powered bulb? What about suspending the lighting high above the tank? Would a single 250W MH bulb over a 48 or 50 gallon tank still provide plenty of light to the plants on the outer edges?

[125gJoe]

This is just what I have read, as I don't have Metal Halides. You should have one MH per two feet of tank length.... Four foot tank needs two MH's..

I sure would like to compare 6700K Compact Florescents and similar Kelvin Metal Halides!! Who's got two I can borrow? :)

[slipknottin]

The most a single MH bulb could cover is about 30" by 30"

You could mount it higher up, but you loose alot of intensity. And the light is far more likely to shine in your eyes when you look at the tank.

[caffeine]

:( just when I thought a MH DIY hood might be cheaper than fluorescent.

Thanks for the information

[125gJoe]

Aren't Metal Halides the most expensive?

[caffeine]

a 250W ballast + bulb and reflector at hellolights.com would be like $150. That's as good or better than ballasts and bulbs for 2x96W CF AFAIK.

[slipknottin]

Two 175 watt ballasts- $46 each
Two 175 watt 5500K bulbs- $50 each
two MH parabolic reflector with mogul base- $30 each

Thats a total of ~$260


Why dont you look into T5 lighting? Its superior to CFs or T8 bulbs.