Metal Halides

[Guest LudavicoTechnique]

If I were to use a 100watt(5500k)  Metal Halide Bulb, would I still need some kind of actinic bulb too?

[vanillabox]

I would not be too eager to use anything less then a 6500 K for my tanks, so I guess my answer is yes.

[Nishant3789]

according to many people ive talked to, 5500K is still suitable for corals, the only real problem is that it looks really yellow, but like u were saying, its easily solved by actnics. hth

nishant

[Metznreef]

if you want to use 1 bulb w/out actinics the bulb will have to be 14000k or more.

[Nishant3789]

From what i kno, it hasnt been proven yet that actinics HAVE to be there for corals to live.... many say yea it IS needed and some say it isnt, and its just there to please the eye... we should start up a thread on that...

nishant

[DAndrews]

Nishant-

 

Atinics are a requirement for most ALL corals.  There have been several studies and showing similar results.  I will also attest to the fact, I ran my tank without any atinic supplimentation and the corals were not nearly as happy as they used to be.  Several things started to go down hill.  Atinic supplimentation is NOT for YOUR viewing pleasure.  It does serve a purpose.  Actually anything 12k or less NEEDS 03 supplimentation.  20k's can go without it, but those too are suggested to have supplimentation.

 

The problem does not lie with the tank inhabitants.  Its with the viewer, not wanting that much blue on their tank, even tho - it does help tremendously.

[Nishant3789]

hmmm well then what about all those people that are useiung lights advertized as actinic but really are just painted blue on the inside?

nishant

[DAndrews]

You might want to go back and read about those bulbs.  They are not painted on the inside.  They are blue and do have some phosphors in that area, but they are not near as effective as true 03 bulbs.

 

(Edited by DAndrews at 2:40 pm on July 5, 2002)

[Nishant3789]

ok sorry, i was wrong, thanks for correcting me,

nishant

[DAndrews]

Wasn't being rude  Just thought you might want to re-read about those bulbs!

 

[Nishant3789]

lol i didnt take it as u being rude lol i was trying to apologize o well

nishant

[Leonard]

Atinics are a requirement for most ALL corals.  There have been several studies and showing similar results.  

 

Please explain what you mean by "results," and direct me to any pertinent studies.

[Jefe12234]

Corals do utilize actinic light. Zooxanthellae have two light absorption peaks at ~ 430 nm and 670 nm. The former is within the actinic spectrum.

 

That does not necessarily mean that you need actinic lights, however. Most full spectrum MH bulbs have plenty of actinic light. Even a 6500K Iwasaki has a lot of light in the actinic spectrum. I ran a 6500K Iwasaki without any actinic supplementation and my SPS corals grew surprisingly quickly. Lots of people do this with prop tanks and get results that are just as good as their actinic supplemented show tanks.

 

So while corals do benefit from actinic lighting, I think that most MH bulbs provide plenty. After all, natural sunlight is not blue. It's about 5500-6000K.

 

To answer your question Ludavico, I think 5500K is on the low side. You may get away without actinic, but I would use some for the corals' benefit as well as your own viewing pleasure. Better yet, consider using a higher kelvin bulb. Some low kelvin bulbs may not have the full spectrum necessary to provide for the different absorption peaks of corals and algae.

 

-Chris

[DAndrews]

Please explain what you mean by "results," and direct me to any pertinent studies.

 

Leonard -  Do a search on reefcentral.  I don't like doing other peoples work.  

 

 

That does not necessarily mean that you need actinic lights, however. Most full spectrum MH bulbs have plenty of actinic light. Even a 6500K Iwasaki has a lot of light in the actinic spectrum. I ran a 6500K Iwasaki without any actinic supplementation and my SPS corals grew surprisingly quickly. Lots of people do this with prop tanks and get results that are just as good as their actinic supplemented show tanks.

 

So while corals do benefit from actinic lighting, I think that most MH bulbs provide plenty. After all, natural sunlight is not blue. It's about 5500-6000K.

 

To answer your question Ludavico, I think 5500K is on the low side. You may get away without actinic, but I would use some for the corals' benefit as well as your own viewing pleasure. Better yet, consider using a higher kelvin bulb. Some low kelvin bulbs may not have the full spectrum necessary to provide for the different absorption peaks of corals and algae.

 

-Chris

 

Jefe12234 -  You may want to refrain from  giving further advice, as you contradict yourself in your reply.  You state that ..

 

"Even a 6500K Iwasaki has a lot of light in the actinic spectrum. "

 

then you finish up by saying ..

 

"Better yet, consider using a higher kelvin bulb. Some low kelvin bulbs may not have the full spectrum necessary to provide for the different absorption peaks of corals and algae."

 

So which is it?  They do, or they don't?  Again, I would readup on your lighting literature and not post any information unless you have some idea of what you speak.

 

Its has been shown and tested that 65k bulbs are NOT effecient for a mixed biotope without actinic supplimentation.  They have also been shown to peak more in the yellow/green area of the spectrum than anywhere else.  You might want to take a look at that.

 

10k bulbs also peak in the blue area, but not as much as an actinic bulb does.  It too requires actinic supplimentation.

 

The only bulb that comes close to peaking in the correct area, is the 20k radium bulb.  It peaks either right on target or just a tad below.  Again, this bulb is also recommended to have actinic supplimentation, but due to the spectrum of the 20k, can do without.  Most do not use actinic supplimentation because it is too blue for the hobbiest.

 

Slapping a 65k on a mixed biotope, does not work.  For SPS, yes as they are closer to the oceans surface, but all the other corals that are deeper, require more of the blue spectrum.

 

Please brush up on your lighting background!

 

DA.

[Smokey Joe]

It depends quite a bit on what you plan on stocking.  Shallow water species don't have the same lighting requirements as deeper water animals, specifically in the actinic department.  While I don't think the 5500k would be catastrophic to most species I agree it isn't nearly optimal by itself.  If you're trying to avoid spending the money to supplement actinic just do what’s been said and get a higher Kelvin bulb.

[NanoReefer53]

for smaller nano-reefs, just get a 150w iwasaki 50,000k bulb (it's not really 50k). The bulb and ballast are pretty cheap and works out to around $120 total. Here's a pic of a tank with the bulb.

 

[Nishant3789]

wow....can u say clams!!!!lol dude, this is what i meant by others haveintg different opinions

nishant

[DaveESPI]

Originally posted by Leonard

 

Please explain what you mean by "results," and direct me to any pertinent studies.

 

 

yep.. I agree. I have the setup over my 37 gal with a prizim pendant and 2 32watt PC..... One of the PC blew lastmonth.. I saw no change in coral growth not to support the need or the LACK of need. The Xouzzant.. does need that spectrum light to preform to optimum ability.. the actinic are supplements.

[Jefe12234]

DAndrews,

 

I have done a good deal of reading on lighting subjects. While I may not know as much as others out there, I do feel that I know enough to share my opinion. Just because you don't agree with it doesn't meant it's invalid. When I said low kelvin bulbs I meant those below 6500K, like the 5500K that Ludavico was asking about. The 6500K Iwasaki is a full spectrum bulb that is succesfully used by many people on mixed reef tanks.

 

I said I agree that corals utilize light in the actinic spectrum. But I also said that they have another absorption peak around 670 nm which is red light, just about the opposite of blue. Mixing these two would give you a white light. I'm curious why you think there is a need for such a blue dominated spectrum. If you're talking about corals that come from deeper waters, then yes, they will be adapted to bluer light. But not because the blue spectrum increases, only because the red spectrum drops off. Providing them with 6500K light is not depriving them of blue light, it's just giving them an excess of red light. This may hurt some species, but will probably help even more. I think 6500K, 10000K, and other full spectrum bulbs provide enough blue light for corals from any depth. I have seen and heard evidence of excellent growth among many coral species with these bulbs, so I believe they are doing their job quite well.

 

-Chris

[dattack]

I agree with Jefe here. The Iwasaki's have more than enough blue than most of the other bulbs and can do well alone even without actinics. I had been running Iwasaki's without supplementation for about 8 months and all corals did well, softies, LPS, SPSs.

 

The few good things about the Iwasaki's is that the loss of intensity in the blue spectrum of the Iwasaki's is very slow and gradual and a bulb can last up to two years. On the other hands, some Ushio's, AB, and other higher K bulbs lose much of their blue spectrum within the first 6 months. Also, the Iwasaki's are cheap and you really don't have to change bulbs for almost 1.5-2 years.

 

http://www.animalnetwork.com/fish2/aqfm/19...es/1/f1fig3.asp

[DAndrews]

Hmm. You all are clueless. The 65k bulbs don't PEAK at the proper levels for a mixed biotope.

 

DA.

[NanoReefer53]

It does somewhat peak in the 400-490 range. Yes, I would agree u can keep a mixed biotope under this bulb but it's not the greatest for the corals who have been under lighting with more blue actinic spectrum.

 

[cal3v]

Yes you can keep it. Not all the corals would like that particular lighting, however. Actinics I believe are not a "requirement". This is my opinion and my experience.