First off, let me address that I think for natives, this is only a good
solution for larger, taller aquaria (which is what Brian was asking
about). I wouldn't go putting a 250 watt halide on a 15 gallon... ;)
With that said, lets discuss heat a little bit...
The "Heat of Halides", to me, is somewhat of a myth.. I think it's
perpetuated by a couple of things and I'll address each indiviually:
1) The Raw wattage of the lamp.
2) The wattage per surface area of the lamp.
3) The misunderstanding that the extra UV and IR the halide lamps put
off is "heat".
The first thing to understand about lighting, with regards to heat is...
"A watt is a watt is a watt." It doesn't matter if it's a standard
flourescent, a pc, halide, an energy saver, high pressure sodium, etc.
It's still a watt, it still has it's own unit of heat associated with
If you were to put a comparable number of flourescent watts and halide
watts in a heat monitoring device, you'd see the same change in
temperature from both. It's the same heat output. However, this is
where Halide gets it's bad name.... In this experiment, for 175 watts,
you had 6 inches of glass envelope on the halide... And you had over
200 inches of nomal output flourescents to achieve the same wattage!
Extrapolate that out to a 400 watt comparison :)
As you can see, the heat generated is dispersed over a greater surface
area in flourescents and they don't seem so "hot", which is a certain
True "Heat" is easy to dispell. If you have an open top tank, you can
just set a regular oscillating fan right on it. A friend of mine put
one of those cheap clip-on fans you can get at Walmat. Evaporation can
dump the temp in an amazing fashion. As well, if you had the halides on
pendants, none of the heat transfer would go to the tank (unless you had
warmed the room).
I'm stubborn and a purist about halide lighting... I still use enclosed
canopies. I use 4" computer Fans to vent my hoods. However, in my
wanning youth, I'm finding myself to be less of a zealot about it (but
maybe that's a general trend ;). When it heated up last week so early,
I wasn't ready to deal with it, but considering that this is 1500 watts
of ligting over 72x18, I don't think it was any reason to throw the
book out on halide, nor do I think *that* lighting configuration is
anything you would want for native aquaria. I will note tho, I didn't
really have to fuss much with the 175w tanks, and I didn't even have
fans on them (which is getting corrected this weekend ;)
So that's pretty much a quick triste on heat.
Now for the fun... The UV and IR. I think this is the single greatest
perpetuator that halide is somehow hotter than flourescents. You stick
your hand underneath a halide lamp, it feels hot right? Is that heat?
I did a demonstration one time at a friends of ours shop. She has a
greenhouse and uses halide to suppliment the SPS coral and tridacnid
clams which are all photosynthetic critters. We had the good fortune
to have the halides on a pulley system, and big big fan to do the
"Put your hand under the light, is it "hot"?"
"Put your hand down by the water under the light, can you still feel the
heat?" (this is about 2.5' from the halide)
"Yes I can still feel it pretty intensely, but it's not as hot."
(turn the fan on.. wind tunnel ensues)
"Put your hand back under the light, is it "hot"?
"Um. Yeah. A little less, but it's still definately hot."
"Put your hand back down by the water. How comperable is that the first
"The same as before!"
I always love seeing shocked faces that look up like "NUHT UH!!!" ;)
It's this extra energy that comes from the halide lighting that endears
it to those of us who use it to rear photosynthetic organisms. In
arguing the case of those critters I say "They've made a living off the
sun... Why wouldn't I give it to them?" :)
With that I'll digress a bit and rethink native. I'm not sure if any of
this really plays into your aquaria, if you're using lights to just
make a nice brite aquarium, or if you're interested in rasing plants,
etc but I have some time while doing an import here so I thought I'd
write a bit about it :) I don't think a well planned system you would
have any heat issues. In fact, for anticipating for the heat, I seen a
lot of aquarists drop their tank temps because they got the floro heated
glass off the top, aquired a real gas exchange, began utilizing
evaporation and etc etc. It may actually be intuitive.
Now there's more that would have to go into just putting new lights on
the tank... There are issues of nutrient conversion that would *have*
to be addressed. You've just given so many new players (algaes) the
ability to step up to the plate, but don't let that scare you. It's
really not all that bad to deal with, and the rewards reciprocate :)
If you'd like to discuss more, poke around the web a bit and see what
others have to say about lighting. It will probably get overwhelming,
mainly because a lot of people are trying to sell you something and they
don't understand it to begin with. But as you have questions, you can
post them here and I'll try to answer best I can (I'm sure there's other
who have experience with all this too).
I'll warn you I'm not into the physics side of things, so if we start
getting into Light Theory, I'm going to step away. I like natural
history, and more so, I like watching natural history work. So at times
in those situations (I'll just confess now) I have a tendency to grab my
"Anecdote Ray Gun" and say "Okay Theory Man. Let's see you grow it!"
thanks todd... a very through speak on the cost of halides, their life
the quality and appearance of the light.
how do you deal with the intense heat and how does that compare to
florescents ballasts as heat generators. i keep many cool water species
have always not considered halides because of their heat.
i do like the way they look at some fish stores i frequent.
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