Gannet--That has been the standard response for a long time, and I agree, they do burn hotter than blazes. But I wonder how the recent findings that corals will grow under any spectrum affect the old theories about halogen?
Larry Willard has been running a reef successfully with mercury vapour bulbs for well over two years now. Sanjay Joshi and Mike at LiCor have only just recently tested out some bulbs Larry sent them. I'm personally really interested in seeing their findings once they publish'em.
For shallow-water (under 3m) zooxanthellar coral, I suspect halogen lights will prove an asset at least aesthetically. The lighting of the shallows is much yellower than fashion in Western reef aquaristics currently allows.
However, I will qualify that the yellow-band intensity comes on for only part of the day (7 hours here, tops). The uneven projection of light (like the focal ring of MH and incandescents) is another weakness. And then there is the damn heat.
As to spectral requirements for coral in general and in specific, that's a topic even hotter than the halogens we're discussing, hehehe. Seems everyone just argues past each other...
Well, I don't know of any "recent findings" that corals will grow under any spectrum, but I'll take your word for it. Not sure what's so recent about it. It's for sure that people tried all the bulbs mentioned here, and all the others too, back when reefing was first getting started. We don't use those bulbs anymore. Wonder why...
Yes, some corals will grow to some extent under any light, NO FL, MV, and halogen included. It's just not smart imo. Lighting is a solved problem in reefkeeping. I don't see why people even fuss over it anymore. In any case, halogen is not the solution imo.
fwiw, imo, ime, ymmv, etc.
when in doubt, change water
By recent findings I was referring to studies by both Dana Riddle and Richard Harker that coral growth was no different under low kelvin temperature bulbs, but for the life of me I can't find the links on these right now. Can anyone help me out?
I agree, the last thing I want is a halogen light under my hood and yes, it does seem like we are constantly re-inventing things in this hobby. Some of that is driven by the high cost of conventional reef lighting, and some I guess is just human curiosity.
I have to admit though, a halogen light shining into the tank makes for nice color in photographing a reef.
I don't think that there is a link to that information. I remember way back, when we were discussing lighting gels, sending you a thread from the reefkeepers mailing list where Sandy Cohen, specifically said that he had been growing corals succssfully under 4300K bulbs. He also spoke of using the gels to alter the light, but found it cumbersome because he was using painted glass instead of the plastic gels. Oh and BTW, the gels solve the problem with heat. They are designed to be placed within 10" of a 1000W halogen bulb. They are safe up to some crazy temperature (600+ degrees C). The heat stays behind the gel.
Please don't take this as a flame, that's not my style. I do however believe that if reefers 10 years ago listened when statments like:
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>. Lighting is a solved problem in reefkeeping <HR></BLOCKQUOTE>
were made, then we wouldn't be where we are now. I think that the lighting industry is evolving just like any other. Halogen bulbs are becoming very popular for a number of lighting applications from car headlights to building lighting. When someone questions the use of a technology it can only help us all. I say push the limits of what is accepted, and find out what is necessary and what isn't. Reefkeeping has just begun... we really have no idea how to do this thing right, yet. In ten years reefers are gonna look back and say, I can't believe they used to do that... kinda like we do now with things like wet/drys. You are more than welcome to your opinion... but please respect that others don't necessarily concur, and that when you make stagment statements, you aren't helping. The idea here is to further our collective understanding. You are probally thinking; "Well you are entitled to your opinion, but I know I'm right.", but if that were true, then people like Mr. Cohen wouldn't be changing the way all of us think about light requirements.
>The idea here is to further our collective understanding. You are probally thinking; "Well you are entitled to your opinion, but I know I'm right."
This isn't the point at all. Lighting is a solved problem, calcium supplementation is a solved problem, filtration for reeftanks is a solved probelm.
That doesn't mean that any particular solution is THE solution. Nor does it mean that my opinions, whatever they may be, are the "right answer". Nor does it mean that further improvement is not possible or worthwhile.
What it means is that we can provide the light, filtration, and calcium requirements of all corals with well-understood techniques. Note that what the requirements of a specific coral are is not nearly so well understood.
Things like nutrition for many species, and sexual reproduction for the vast majority of species, are unsolved problems.
fwiw, imo, ime, ymmv, etc.
when in doubt, change water
I see your point. In the sense, that we know what lighting ranges most corals need, lighting is sovled problem. I think that what REEFA was asking is: "Does anyone know if halogen lights can provide adequate lighting for my corals?" Good point. Thanks (especially for not taking my words as a flame.).
I think that you can use a halogen light with a stage lighting gel to provide the proper lighting requirements and an aesthetically pleasing tank. I have only seen MH and MV lighting with the stage gels, but the gels are designed with halogen lights in mind. ROSCO, Inc. has temperature correction gels, or gels that will "change" the halogen light to say 5500K. This gel will reduce intensity, but might be a cost effective solution if you use a more intense bulb (ie, use a 1000W light to get 400W worth of light). The gel will also help with heat management. Our forum moderator badgers, happens to be a lighting expert, so you might seek out his opinion as well.
Halogen Lamps would need the equavalent in savings to be spent on cooling fans
It might be asking for a fire running these lamps above your tank. I recall LOA changed their halogen torchiere (sp?) lamps to PC because dust collection was a potential fire hazard. These things are really, really hot. I bought several of them for a painting company I ran a couple of years ago as a summer project. The bugs were attracted to the lamp, and would 'fry' to the lens. Whadda mess.
I still think that MH in this industry has a long way to go. I'm still looking at the liquid-cooled MH in the hydroponics industry and wondering how long it will take for our hobby to duplicate this. I also have high hopes for the DC MH bulbs (dimmable) right now coralife is marketing these, and they haven't taken off... yet.
I'm not sure if we've solved too many problems yet, but we've sure improved on some methods.