# Halogen = Metal Halide?



## tommyboy22481 (Mar 24, 2004)

I just bought the book "Encyclopedia of Aquarium Plants" by Peter Hiscock and published by Barron's. While I was reading through the lighting section it started talking about Metal Halides and I quote "Metal-Halide, or halogen, lamps provide intense, high-output light via a tungsten filament." and "Halogen lights are initially the most costly method of lighting, but provide the best output for demanding aquarium plants." I was under the impression that Metal Halides were awsome for plants while halogen were junk, but this seems to say that they are basically the same thing. 

Is the author crazy or are my Halogen lights just as good as Metal Halieds?


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## malkore (Nov 3, 2003)

I think halogens and metal halides are the same kind of technology, as far as how the bulb works.
However halogens don't need a ballast, and halides do.
I have that book, and it's pretty good. I'll have to re-read that section, because, yes, halogen's have a poor spectrum and don't do much for plant growth. MH have a good spectrum and are find for plants


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## equilibrium (Feb 26, 2004)

malkore said:


> I think halogens and metal halides are the same kind of technology, as far as how the bulb works.
> However halogens don't need a ballast, and halides do.


Yes, sort of.. Metal halide are highly specialized. That's why you can get a 400 watt shop light for $20 but the same wattage MH will cost you megabucks..

Even though I don't have a nanoreef I like to lurk over on www.nanoreef.com for their extreme techiness. Some people over there are buying shop lights with double ended fixtures, retrofitting them with UV blocking glass, hooking up a ballast, and dropping an MH bulb straight into the fixture..


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## rkundla (Mar 25, 2004)

Halogen bulbs and metal halide lamps are like apples and oranges in how they work although they have a common element, the use of halogen elements from the periodic table.

Halogen lamps use a tungsten filament in a bulb with a particular halogen gas element to keep the tungsten from getting blown away in the filament when heated. Metal halide bulbs use a combination of metal halide salts which are vaporized by an electrical arc creating plasma.


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## malkore (Nov 3, 2003)

thanks for the clarification!


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