Lighting for Reef  -02/20/08
Hi,
I don’t know when you wrote your post on Marine Lighting.
<Last time in about the mid 90's>
I’m just considering a reef aquarium, and would like to know if you still prefer Vita-light and Vita-light supreme, or do you think T5 is a better plan?
Thanks for your help.
Brent
<Mmm, for what application, desired results...? Both, all are fine technologies and Dura's products are well-engineered... There is much recorded on WWM, linked re approaches to photonic application to captive aquatics... Perhaps a re-reading/scanning there. Bob Fenner>

Lighting DOWNgrade!  9/30/05
Great site!
<Glad you like it! Scott F. here today!>
I know there have many question submitted such as what I am going to ask, so I apologize beforehand for redundancy.  I have just printed an article by Anthony Rosario Calfo titled, "Reef Lighting Without Controversy".  It was a helpful article as were the many WWM FAQ's I tried to sift through.
<Yeah, I know that guy...He knows a few things about coral...heh, heh heh...>  
My scientific vocabulary is weak at best so here are the common names of what's in our tank:
Colt Coral, Green Finger Coral, Soft Leather, Hairy Mushroom as well as several other types. Pulsating Xenia and a couple different types of polyp.  My wife is 100 times better at nomenclature than I am... but I am the one asking this question.  Everything in our tank is/has been thriving for the last 5 years with our current setup.  What we want to change is our lighting.  Currently we are running two 20000K 400w radium bulbs and two 4' blue actinic VHO's all attached to the lid of a 12" canopy with two 7" fans for ventilation .
<Sounds like a beautiful lighting set up for your inhabitants...Must really fluoresce them.>
The lights are approx. 8"-10" from the surface of the water (tank dimension are 72x24x24).  NO!  We are not making lava!
<But you could...LOL>
This is how it was designed from our former LFS.  I realize that this may be a bit much for lighting.  We want to down grade to 10000K 175w or 250w.  What would be considered practical and efficient lighting for the coral I mentioned?
<I'd think that a good "downgrade" would be 150w or 250w double ended (HQI) pendants, like ReefOptix or Giesemann make. Don't fool yourself, though- these pendants and configurations can throw a lot of life that can still shock corals if you're not careful.>
Will there be significant shock to the marine life?
<Any lighting change-up or down- can be potentially shocking to sessile invertebrates. However, if you are using the same spectrum of bulb, and carefully acclimating the animals to the new light (i.e., shorter photoperiod, possibly using screens to acclimate the animals to the new light source), you should see some good results...and a lower electrical bill!>
Is it possible to direct me toward some helpful information or can you easily give me a ballpark answer?    
<I'd continue to read the writings of Anthony, as well as the many helpful articles by Sanjay Joshi on reef lighting.>
Thanks for ANY help you can provide,
Jim
<My pleasure! Regards, Scott F.>

Question About CRI Colour Temperature and UV Filtering  9/17/05
Hi Crew, <Hello Brad>
I looked in the posts to try to find the answer to this question. I found the question was asked but I did not understand the answer posted.
I am researching metal halide systems and found that bulbs in the 5000 to 5500K range have High 90+ CRI values. When looking at higher temperature bulbs (10000K) I notice that the CRI drops to around 65. These numbers are taken out of manufacturer catalogs for commercial bulbs. It makes sense to me that the CRI will drop the further you get away from the 5500K  mark. I just want to ask if my assumption is correct,<Yes> or if there are some special marine designed bulbs in the upper temperature range that have higher CRI values. <A color rendering index of 100 would be equivalent to high noon in the tropics, that is, the most natural color.  A lower CRI does not necessarily mean the light is no good for your corals as certain wavelengths filter out very quickly the deeper the light penetrates the water. These high temp bulbs at the proper wattage per gallon (4 to 8) provide enough intensity for the corals to live.  The higher temperature bulbs (10K+) are closer to the color you would actually see on the reef.  Hope this makes sense.  Just got back from the madhouse in Detroit and the mind is foggy.>
I also read in one of your articles that unshielded bulbs can put out dangerous UV A, B,& C rays and must be filtered. Is a piece of glass placed on the output end of the fixture adequate to filter these harmful rays, or are there special lenses you need to get for filtering purposes. If you need special lenses do you know of any sources?  <Glass works, but acrylic is better, no special lenses needed.>
Thank you for your help. <You're welcome, James (Salty Dog)>
Brad

- Lighting For Corals -
Hi!
Just found your website a few days ago - Wow! I've never seen so much current and useful information on marine aquaria in one place. And the amount of time you guys spend answering questions and otherwise assisting fellow hobbyist is just incredible. You guys are terrific.
About two years ago my daughters bought me a twelve gallon Eclipse tank, some marine salt, a little crushed coral and a yellow tail damsel for my birthday. Since then I've changed to a live sand bed, added lots live rock, a few fish and some low light (mushrooms, etc) corals. All are doing well. (oh, and I hear my daughters are okay too... I spend most of my time with my nose pressed against the glass of the aquarium...). I've got my eye on a 100 gallon acrylic tank and as soon as I can convince my wife we can't live without it (and I'm so close!!!), it's mine.
Even though I'm still fairly new, I already know that water quality is number one. It's like the air we breathe. Can't go for long without good air and those guys can't make it for long without good water. But we're able to measure water quality right down to the millionth part per gal/ltr, so there's really no excuse for poor water quality. It seems another major issue and my concern/interest right now is lighting for the reef tank. All I ever see is "low, moderate and high". Just what the heck does that mean? <Pretty much exactly what it sounds like - depending on the animals you choose, the lighting will need to suit their needs. Of course, tank depth is also a variable, but for the most part low intensity lighting refers to normal output fluorescent lighting. Moderate intensity lighting refers to VHO or PC fluorescent lighting, and high intensity refers to metal halide lighting. Quantities and color temperatures will vary based on tank size and depth and also the age of your bulbs. Please read here: http://www.wetwebmedia.com/marine/setup/lighting/index.htm > It all seems so ambiguous in such a scientific age! I know there are all kinds of sophisticated scientific gadgets to measure light that are not available to the average hobbyist, but surely we can do better than "low, moderate and high". <Read on, you will see...> In the things I have read, I have learned that at the surface of the water in the tropics, at noon on an average day, the sun provides about 100,000 lux of 5500K light. Within fifteen feet, the reds and oranges are absorbed and the lux are down to about 20,000. By thirty feet, the yellow light is gone and the lux have dropped to 10,000....etc. <Well... you realize that no amount of mechanical lighting will ever equal the output of the sun, and likewise very few people have 30 foot deep tanks.> Okay, finally, here's my question! Has anyone gone to the trouble of making up a simple chart for salt water aquarist that would show this progression of light reduction and Kelvin temperature change as the depth increases? <Not that I am aware of, but still... the amount of light you choose to use is dependent on the animals you choose to keep - Tridacnid clams for instance must have metal halide lighting or they will not thrive. Fish on the other hand, don't require this type of high-intensity lighting... so, is your budget for your electric bill unlimited? If so, light fish with any lighting you choose - for the rest of us, there are offsetting choices that must be balanced between the acquisition/operating costs of a particular type of lighting and the animals we want to keep.> I know there are variables such as water clarity, etc., but a general chart could be developed... and here's the payoff. By identifying the various corals at the depth in which they are usually found, it would be possible to much more clearly identify their light needs - or at least the range of lighting conditions in which they are most likely to flourish. <Essentially, this much has already been determined, and again low, moderate, and high does suit the bill.> Sure, it might mean I'd want to go buy a $100 light meter, but I'd rather do that than guess whether my corals are getting enough (or too much) light, or whether I need to move one of them to a healthier location in the tank. <Do you have a specific animal and tank size in mind here? That might help answer your questions - or as you mentioned, to satisfy your own curiosities, you might just want to track down and purchase a lux meter.>
Maybe such a chart or publication already exists, or maybe - being new to this hobby - I've overlooked or over-simplified something that would not make this idea practical, but it just seems we can do better for our little critters than "low, moderate, high". <Not sure we'll agree on this, but it's been working well for a while now.> Your advise/comments would be appreciated.
Thanks.
Rick
Venice, Fl
<Cheers, J -- > 

Lighting for corals
Hi Bob (and all the other good folks!)
With your advice and some wonderful references, I now have two thriving reef aquariums- one 55g and one 10g which is a constant source of amazement- it is literally TEEMING with life forms, with new creatures being discovered daily.
<awesome to hear!>
With this success behind me (wink), I am considering moving on to corals (in the big tank, although it looks like a tree-like coral is growing in the small tank). Having read most of the literature on lighting, I am confused on some things.
1) Light is preferred at 1-2 watts/gallon, so it seems, yet much of what I read would indicate double that requirement- is more better? I don't want to burn them...
<the watts per gallon rule is complete bunk. I explain it and likely most of what you are wondering here:
http://www.wetwebmedia.com/marlgtganthony.htm
do follow up with questions if necessary>
2) Metal Halides seem to be preferred, yet one source states they are unnecessary if the water is less than 18" 
<agreed essentially>
and another source claims they need remain on no longer than 2-4 hours daily...
<disagree here... MH lamps are ideal lights for tanks over 24" deep and they are in fact the most economical light (bang for your buck). Shallow tanks simply may not need them and no discussion of water depth is relevant without first identifying the corals that will be kept. We must ID our corals on a guest list or wish list before we can buy lights to suit their needs. Do your self a favor and try to stay with one main group of corals and not mix a little of everything. There are many complications with the typical mixed garden reef that has LPS, SPS, soft corals, Zoantharians, etc all mixed together. Stick with Soft corals only most likely>
if I keep soft corals, within 6" of the water surface, do I require them? I have 1 actinic 40w bulb, 1 daylight (10,000k ?) 40w, and two 15w standard aquarium fluorescents- 110w total.
<2 175-watt 10K Aqualine MH lamps would be ideal IMO if you like higher light animals (colored leathers, clams, sps). Or, if you stick with hardier medium light animals... 4-6 110watt VHO bulbs will serve you well>
Once again, effusive praise and accolades...but seriously, I DO appreciate both your wisdom and your timeliness on responding- I could not have made the 55g a success, let alone the 10g, without your guidance- that goes for the whole team. Gerry Sames
<wishing you the best! Anthony>

Coral Lighting
Bob,
Great site. 
<thanks kindly>
I have a 75g tank (48x19x20) currently with an Ice cap system. 1-Actinic blue and 2-actinic daylights (46.5" 110 watt bulbs). 
<still... corals must be kept in top 10-12 " for best health>
I have about 60# of Fiji rock and about to add 20# more prior to adding coral. Is this lighting adequate? I was thinking of adding one more bulb possibly the URI actinic sun. What do you think? Is more better?
<to some extent... but it still doesn't change the fact that fluorescents do not penetrate very deep... no matter how many lamps are above. See here for more information: http://www.wetwebmedia.com/marlgtganthony.htm >
thanks DJ<best regards, Anthony>