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Halogen Lights


  1. Alternate Lighting
    by (John Raithel) (Fri, 4 Mar 1994)
  2. Any usefulness out of halogen lights?
    by (WRIGHT HUNTLEY) (8 Mar 1995)
  3. Any usefulness out of halogen lights?
    by (Craig Bingman) (12 Mar 1995)
    by (Craig Bingman) (23 Jul 1995)
  5. Halogen light for plant??
    by (Raymond Chan) (11 Oct 1996)
  6. Cheap, strong light?
    by "David W. Webb" <dwebb/> (Fri, 29 Aug 1997)
  7. Halogen Egg "Lites"
    by "Roger S. Miller" <rgrmill/> (Sun, 21 Mar 1999)
  8. Halogens
    by Thomas Barr <tcbiii/> (Sat, 05 May 2001)

Alternate Lighting

by (John Raithel)
Date: Fri, 4 Mar 1994

In article <2l3vp0$>,
Ken Johnson <> wrote:
>We're all familiar with flourescent ($$$) and metal halide ($$$$$) lighting.
>Has anyone ever experimented with some of the other high wattage (but cheap)
>lighting such as quartz or halogen? I've seen 300 watt quartz spotlights 
>for $25, so of course, I wonder...

Omigod.  300 watts of quartz halogen.  I'd recommend you place it
about as close to your tank as the sun is.

But seriously, I use halogens (not halides to address another post)
with some success but they have unique requirements:  

1) First of all, they generate a very focused light - a spot light, 
even on the so-called "floods" tha I'm familiar with.  

2) Second, they do generate a lot of heat.  If they are close to
a tank, and especially a small tank, this can cause considerable 
fluctuations in daily water temps.  

3) Third, their wavelength peaks do not correspond to the wavelengths 
plants prefer (if that sounds a little vague, its because I'm - 
the particulars are well known by the light and plant gurus in this 
group and they can and have explained it much better).

So... why would I use the suckers?

1) I like the spot effect.  I like to highlight areas of my tanks and
not have a uniform light throughout.  And, some plants need a lot of
light, some require less - plants can be arranged in the tank to take
a good hit or sleep in the shade.

2) The heat is a problem I deal with by attempting to keep the lights at
a reasonable distance from my tanks and on for a lenght of time I've
determined does not cause much fluctuation.  I can live with some
daily fluctuation... 2 - 3 degrees.

3) This light, IMHO, is beautiful.  It looks like a beam of sunlight and
borders on the hypnotic in a darkened room (to human observers I mean).

*) And finally, I've had good luck with plants.  The plants I grow are
suited to my water (7.8pH and fairly hard).

So, you might try halogens.  They take some more planning,  On my
most recent tank, a 100G, I mix one 50W halogen (1 foot above in the
middle) with a flourescent hood with 2 20watt flourescents.  

- John

p.s. question: I'm curious about the fact that I have had good luck
with plants (crypts, anubias, sagittarius [why do I hear of and see no
sags at stores?], and vallisneria) in apparently unfriendly spectral
output.  I wonder if the very intensity of these halogens doesn't
produce some good amounts of light in the areas of the spectrum that
are not its peak areas....?

John Raithel       And I must be an acrobat
                        to talk like this and act like that. - U2

Any usefulness out of halogen lights?

Date: 8 Mar 1995
Newsgroup: alt.aquaria,rec.aquaria,sci.aquaria

In <3jl7an$> "David W. Webb" <> writes: 

As long as we are adding our miscllaneous $0.02, I too have a couple of 
little changes:
>(e-mail) (Erik Olson) wrote:
>> Halogens are basically incandescent lights.  The difference is that
>> instead of a vaccuum, the bulbs are filled with a halogen gas
>> (flourine?  Chlorine?  I don't know) to improve the filament's
>> stability. 
>I've got a little change to your statement.  Halogen bulbs are 
>vacuum/inert gas bulbs, just like incandescent bulbs, with two 
>1.  A hotter filament.  In a standard incandescent bulb, a hotter 
>    filament would evaporate quickly and the bulb would burn out.

The hotter filament also means a color temperature that is considerably 
higher than a normal 3200K incandescent.

>2.  Halogenized glass.  This glass repels the filament particles.  
>    They re-deposit on the filament, sustaining the life of the 
>    bulb.  If you touch the glass with anything that reacts
>    with the halogen (like your finger), the bulb will quickly 
>    burn out.

Halogenized glass? I never heard of a halogen lamp made of anything but 
fused silica or some equivalent refractory glass. They burn out from 
fingerprints or other contamination due to the excess heat absorption 
and (maybe) the fluxing action of the sodium chloride in your 
perspiration that causes the bulb to fail by melting. The halogen just 
ain't present out on the outer surface. The glass runs extremely hot as 
part of the halogen cycle inside, so normal soda-lime glass would 
quickly melt at temperatures that permit the replating of the filament.

Some side issues ---

The fused silica (sometimes misnamed fused quartz) passes much more 
energy outside the visible than soda-lime glass, hence it is very 
hazardous to operate halogens without a window-glass cover of some kind. 
Both your eyes and your skin can be injured by the excess UV, and the IR 
may be a causative agent in cataract development. Be just as careful as 
you would with metal halide and actinic flourescents.

The earlier objection that they are too hot for aquaria is a very valid 
one. You need LOTS more watts in to get the same watts out (as 
flourescents), so you could cook your fish by the time algae starts to 
form. No thanks.

The heat was a real problem when I was measuring cover-glass loss. 
Heating of the samples caused so much secondary IR radiation that I had 
to take very quick readings, before sample heating started to shove my 
"zero" all over the place. I don't want that in my tank in the summer.


"The first (and key) step to liberty is to be a good neighbor."

Any usefulness out of halogen lights?

by (Craig Bingman)
Date: 12 Mar 1995
Newsgroup: alt.aquaria,rec.aquaria,sci.aquaria

In article <>,
Mitch Black <> wrote:
>I believe I read somewhere that halogen lights were not useful
>for aquarium purposes; in particular, regarding their use for
>reef environ.  Can anyone provide a scientific base/refutation of this?
>Careful.  What I am looking for here is not opinions, or "I heard...",
>or "I read in FAMA...", unless there is a strong scientific basis
>behind it (whether controlled experiment, or scientific analysis).

Damn, mitch, good thing you showed up and saved us from all this
hearsay and non-scientific thinking.

I ran a halogen light briefly over an aquarium when I was a 1st year
grad student in Madison.  I believe it was a 300 watt halogen flood.
It produced immense amounts of heat, and it was extremely good at
growing problematic algae.  In the winter, it helped to warm the
apartment, in the summer, it tended to cook everything.  I wound
up putting it over a tank of adult brine shrimp, where I was Trying
to culture green algae, and the shrimp don't mind the heat.

The efficacy (lumens/watt) of halogen bulbs, and all incandescent
bulbs is roughly one quarter to one third that of fluorescent or
metal halide sources.  That means you get roughly 4x the heat production
for the same quantity of light.  When you consider that many reef
aquaria are running on the razor's edge of needing a chiller, or
requiring a room air conditioner to be run hard all summer long,
you will see the folly and false economy of trying to persue these
sources for reef aquarium use.

To get as much output as a 175 watt metal halide lamp, you are going
to need more that 2 300 watt floods.  And the spectrum will be heavily
red weighted, which isn't what you want.

>Of course, I'd tend to believe a *reliable* source, but those are few
>and far between, as we've all read the conflicting articles, books, 
>heard the opinions, etc.  - I'd consider something like Sprung to be
>a reliable source (as I'm guessing it would meet the requirments 
>I set out regarding the basis for making the assertion).  

Why don't you buy the Delbeek and Sprung book, then?  



by (Craig Bingman)
Date: 23 Jul 1995
Newsgroup: rec.aquaria

In article <3ujlr1$>,
David Waisman  <> wrote:

Sorry about that, time to have a word with the communications officer.


Many have tried.


They are also incredibly inefficient compared to metal halides or
fluorescent lights.  So cheap to buy, not at all cheap to operate.
The fall into the penny-wise and pound foolish category.

Power here costs over 12 cents/kilowatt hour.  Let's say 10 cents
to make this easy on me, and to also keep the math simple, let's
say you are putting a hypothetical 250 watt metal halide your
tank, or a halogen flood that makes a comparable amount of light.

Since the efficacy of halogen floods is about 1/3 to 1/4 that
of metal halides, that will take between 750 and 1,000 watts
of halogen flood.

The metal halide will take 250 + ~50 watts of ballast loss to 
run, say .3 kilowatts/hour.

Equivalent floods will take 1 kilowatt/hr to run.

They are going to be on ~10 hours per day for 365 days per year.
That is 3,650 hours.  Call it 4,000 hours, to make my life a bit

The metal halide is going to chew up

(.3 kilowatts)(4,000 hours/yr)(0.10 dollars/kilowatt-hour)= $120/yr

The halogen floods are going to run

(1 kilowatt)(4,000 hours/yr)(0.10 dollars/kilowatt-hour) = $400/yr

For a difference of $280 per year in operating costs.  This totally
neglects the effect that a continuous 1 kilowatt heat source is going
to have on your AC bill in the summer, and the probable need to 
obtain and operate a chiller.

One can get a perfectly reasonable metal halide fixture from a hydroponics
place with a high color temperature lamp installed for less than $280.

So, you are going to break even on the metal halide system in less
than a year, completely ignoring the major problems of heat disappation.
If you happen to set it up now, when you are running your AC, then the 
breakeven point is probably a few months.  After that you save money.


It is very yellow, low color temperature, mid 3k range at best.
It isn't ideal, by anyone's definition.  The halogen floods are
OK at growing algae.

People have done this before, it just does not work out well.
It isn't good for the animals, it isn't good for your pocketbook.
Metal halide and electronic fluorescent look expensive from the front end,
but they are the only way to go if you plan on keeping the tank for
more than a couple of months.

Maybe we need to add an explicit section on this in the RK FAQ.  This
is twice today I've wound up answering the same question.


Halogen light for plant??

by (Raymond Chan)
Date: 11 Oct 1996
Newsgroup: rec.aquaria.freshwater.plants

I have used a halogen light on my 20 gal.
the temperature moves up by about 10 degrees in 4 hours.

I can't say that the results have been spectacular.
however, I do know that some photosynthesis is going on because I had a
carpet of blue green algae which I treated with erythromycin
(transcription inhibitor).  The part of the tank that I shaded from the
light had almost no die back while the other parts did.

Raymond Chan

Cheap, strong light?

by "David W. Webb" <dwebb/>
Date: Fri, 29 Aug 1997

>Date: Thu, 28 Aug 1997 09:29:19 -0700
>From: "Frank I. Reiter" <>
>Browsing through a hardware store yesterday, I came across some halogen
>lights and suddenly realized that I have never heard any mention of
>trying them over an aquarium.  With there being no expensive, bulky, noisy
>ballasts, and with 500W bulbs costing $4.00, somebody must have tried

There are some good articles on halogens in the APD archives to check out.

>Does anybody know anything about the spectrum that these things put out,
>failing that, how I could find out?

Okay, here's the thing about halogen and other incandescent bulbs.

Halogens and incandescent bulbs are a blackbody-type radiation source.
They emit light energy in all wavelengths from the deep infrared up to
their operating color (color temperature, effectively).  Halogens run at a
hotter temperature than normal incandescents because the gas in the bulb
helps prevent filament degredation at the higher temperatures.  This gives
them a higher color temperature than say, a normal 40w, 100w, ...

A large part of the energy emmitted by incandescents comes out in the deep
infrared range.  Some of this energy is useful to plants, but some probably

What you get out of an incandescent light is a CRI of 100, every time.
It's just the way they work.  They acheive this by emitting light in every
wavelength.  In order to do this though, they use a lot more energy than a
fluorescent or other plasma discharge light that restricts most of its
output to the visible spectrum.  

In terms of efficiency, well, that depends on what you want.  An
incandescent will emit 100% of the energy it consumes, minus conductive and
convective losses.  The challenge is that a big part of this is not visible
light.  A plasma discharge has additional, small energy losses at the point
of the ballast, where the energy is dissipated as infrared or by
conduction/convection.  An additional, fairly small percentage is radiated
as infrared from the light source (tube or bulb), but a very large
percentage, comparatively, is emmitted as visible light.

I've heard of great successes using incandescent lighting.  The thing is,
your tank won't be as bright per watt-hour consumed, and you may run into
heat problems.

I use fluorescents and would consider other plasma discharge lighting.  If
I want to do incandescent, it will be experimentally on a very small scale,
or it would be using direct sunlight.

I hope this helps some,

David W. Webb           Texas Instruments
(972) 575-3443 (voice)
(214) 581-2380 (pager)

Halogen Egg "Lites"

by "Roger S. Miller" <rgrmill/>
Date: Sun, 21 Mar 1999

On Sun, 21 Mar 1999, Mike G. wrote:
> Was doing some surfing the other day and ran across these curious little
> submersible halogen lites at and wanted to pass it along to
> the list.  For those hurting on lighting and especially those who have
> trouble getting to the bottom because of dense growth or what have you,
> these may be useful.  I know there alot of ingenious people on the list and
> if this helps one person solve a problem then I've done my job.

My favorite local shop was selling submersible halogen lights quite a
while back, though maybe not the same design you're writing about.  They
looked to me like an interesting way to accent a special plant or an
attractive niche in an aquarium, so I asked the (honest, experienced)
sales person about them and she said they generated too much heat for
regular use.

Roger Miller


by Thomas Barr <tcbiii/>
Date: Sat, 05 May 2001

>> Just saw an add on TV for some really cheap halogen lights.. like 150W and
>> 500W ones....  what are peoples experiences with these and are they >suitable
>> for planted aquariums ?
> Stay away from them. They give off much too much heat and have a relativly
> low (2800-3200 K, approx, maybe 3600 K tops) color temperature light.

The color temp is not bad for plants and will do very well for most every
plant. The heat, efficiency, and color to our eyes is another matter.
I grew 200 different species quite well with them but they vary in
The 150-500watt types are not very good IMO. The GE "color precise" 50 watt
track lighting 12v did the best of the all of the ones I tried. Looked the
best too(3050K). You can get the "spot" narrow focus bulbs and add this to a
MH set up for a very neat affect that will not heat the tank up much. These
spots can be placed 2-3 ft or more away from the tank. The floods are more
for the 12 inch distance range. I tested the heat from 3 x 50 watt lights at
12 inches for a 20 gallon tank and got an average of about 1-2 degree (C)
rise per photoperiod of 12 hours. This took into account ambient room temp
changes vs a FL T-12 set up with 60 watts of light as well. There's about 2x
the light coming out of the FL T-12's in this set up. But you pay for over
2x the electric. I flowered Crypt parva submersed using them. *If your after
bright and cheap, T-8's are hard to beat.

They have their place in small tanks/spot lights/dimmable lighting accents
but not a main source for any long term project/ big tanks etc. I messed
with them for about 5 years in a lighting quest. MH's/PC's/T-8's/T-12's are
cheaper in the long run. Might not seem like it at first but they are if you
look at the long term.
Tom Barr 

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