Lighting Article

[pat8you]

ok so i have been doing a lot of reading on lights recently so i thought i might write up an article as i went along since i see questions on it fairly often. Tried to keep it a general/ non-technical article about lighting specifically a reef and a little bit about how that relates to the corals and animals we keep.

That being said, this is a big topic to cover and it would be quite bold to say that i have all the right answers here. I am looking for all your guys help to make sure what i have is correct and I'm not leaving things out of this article. I would really like to hear others opinions. If you have something you think should be added or revised as long as there is some kind of concensus about your opinion being correct i will happly add/change it in the article.

Some things i know i need help on here are
-a breif explanation of actinic lights
-the differences between single and double ended MH bulbs (think one of them is sapposed to have problems with UV?)

The main thing i really need input on because i don't feel i have enough experience to do this section justice is some general guide lines for lighting of different corals. I started to put together some charts at the bottom and figured i would let people help me complete them. I thought it would be good to include anemones and clams as well.

So let me know what you think. All opinions/criticisms are more then welcome. you won't hurt me feelings i promis.

 

[pat8you]

Lighting for a Reef Aquarium

Introduction –

This article will focus on lighting a reef aquarium and some general guide lines about the requirements for corals. This is meant to be a relatively general overview of lighting and attempt to cover the subject in a somewhat non-technical manner. Please keep in mind that reef lighting is a highly debated subject. In a room full of 10 hobbyists, it is unlikely that any two of them will have the same set up over their tanks. This subject can also be very complicated and some of the links provided at the bottom of this article go more in depth to particular aspects of light. I don’t claim to be an expert so use this information as once piece of your research that will help you make an informed decision about what lighting set up is right for your tank.

Evaluating light quantity and quality -

You will often hear people try to quantify the amount of light in a reef by the watts per gallon rule. This is done by simply dividing the total watts your system puts out by the number of gallons in the main display. This is a good place to start but much more information is needed to really decide if you have enough light for your corals. There are several other factors that should be considered.

A watt is the amount of power that a bulb has and is the measure of energy delivered per unit time. Intensity is another important factor that should be considered in choosing a light source. Intensity is the measure of power delivered per unit area, so this would translate to energy per unit time per unit area. Obviously increasing the amount of watts of light will also increase the intensity but the type of bulb also has a large effect on intensity. Metal halide bulbs emit light from a single point as opposed to over a relatively long length of a fluorescent bulb. This gives MH fixtures a greater intensity and causes the nice shimmer effect in the water as the surface ripples. So 100 watts of light from MH will have a greater intensity and provide more energy to your corals then 100 watts of fluorescent because it cannot all be concentrated in as small an area.

The last aspect of the light to be considered is the color spectrum and K rating. Light can be considered a wave and it can have different wave lengths. Light with a short wave length is going to appear more violet and blue. Longer wave lengths are going to be red and yellowish. The K (Kelvin) rating attempts to give us an idea of what color spectrum a bulb outputs. Natural sunlight has a k rating around 5500˚ and has a good balance of all the colors in the spectrum. The higher the k rating the more blue the light will appear. Even a 20,000k bulb will have the other colors in the spectrum, but a much larger percentage of the light will be blue/violet. Many hobbyists believe that corals use blue spectrum light the most efficiently. The deeper in water your go the more light is absorbed starting with the red end of the spectrum and working its way down. So as you go down from the surface on a natural reef you will find more blue and less of the red, yellow, and green. Most of the corals, anemones, and clams that we keep in our aquariums are collected from relatively shallow depths where the full spectrum of light is present and so are not particularly adapted to use blue light any better then the other wavelengths. Some deep water corals (15-30m) may be better adapted for blue spectrum light. So what does this mean for you? Unless you know specifically what lighting spectrum all your corals prefer, give a fairly broad spectrum that you think looks good over your tank. Many hobbyists prefer the more crisp white (10,000k ish) to blue tint in their aquarium instead of the lower k values (5500 – 6500k) that give off a more yellowish tint.

Types of lighting –

Before discussing the different kinds of bulbs it is worth mentioning that a bulb is only as good as its reflector. Keep in mind that bulbs project light in all directions but we are only interested in lighting the narrow field of our aquariums. If a fixture has a poor reflector then much of the light put out will be wasted by not being channeled back to our aquariums where it can be used by the corals. The best reflectors will have one for each bulb and be parabolic in shape. The closer the shape of the reflector resembles a parabola the better.

Fluorescent - These bulbs were some of the first available in the hobby and come in a huge variety of options. Fluorescent bulbs are best used in more shallow tanks (<20” apporx.) because the lack the intensity to deliver good lighting as tanks get much deeper then that. They do how ever run at much cooler temperatures then MH lighting so heating the tank is not as much of an issue.

Output
NO (normal output)
HO (high output)
VHO (very high output)

This just means that the bulbs/ballast have been tweaked to output more light and run at higher wattages as the name suggests. The bulbs and ballasts are not interchangeable. You cannot run a VHO bulb in a normal output fixture.

Size
T-5 5/8”
T-8 1”
T-12 1 1/2”

This is on a scale of 1/8” (T-12 is 12/8” or 1 ½ ) and is just the diameter of the bulb.

Compact Fluorescent – These bulbs are very similar to fluorescent bulbs as you might imagine. Multiple bulbs are sandwiched together and share a common socket. They come in different combinations of K ratings to meet different aquarium needs. They have the advantage of higher light output in a small space. They work particularly well for nano reefs for this reason.

Metal Halide (MH) – This type of system is often left for reefs with animals that require high amounts and intensity of light. It is also good for larger tanks because of the depth. They come in single and double ended bulbs. Typically the standard wattages found are 150, 175, 250, 400, and 1000. A major concern with MH is always heat. Since they run so hot fans or in extreme cases chillers are needed to ensure that the water temperatures don’t rise too much during the lighting period. These systems also come at considerable expense. If your handy DIY can save a lot of money and is not a complicated task with a little research. Most MH reflectors will have a range of heights to mount the fixture. The higher the fixture is mounted the larger area it will cover but will provide less intensity. As a general rule a MH bulb and reflector will cover about a 2’x 2’ area.

Which ever type of light you choose, replacing the bulbs should be factored into the operation cost over the long term. Liveaquaria.com provides some guidelines for suggested replacement times for each kind of bulb at the bottom of this webpage.

Aquarium Lighting: Frequently Asked Questions Regarding Aquarium Lighting

Corals and Critters –

Since the average hobbyist does not a have light meter to measure the intensity or spectrum of their lights I will continue to use the watts per gallon rule as a starting place for recommending some approximate lighting requirements for common animals found in our reefs. Keep in mind this is only one factor in caring for these corals/animals and only just a place to start for their lighting requirements. Placement in the tank, flow, special feeding, and how hardy a particular specimen is should all be taken into consideration.

SPS
Common name
Scientific name
W/gal
Acropora*


Pocillopora*


Stylophora*


Montipora*



LPS
Common name
Scientific name
W/gal













Softies
Common name
Scientific name
W/gal












* designates animals that are recommended to be kept under MH lights for best care

 

[pat8you]

oops sorry the charts didn't transfer over well from word. just ignore those big spaces at the bottom. The common name, scientific name, and your recommendation for a w/g will be what i need to fill in the chart. Hopefully everyone will be able to come to an agreement on some of these : )

 

[SpeedEuphoria]

I'm not so sure 20" is the magic depth where tube lights become less attractive

 

[ccCapt]

It's pretty cool you took the time to put this all together, but for an article, something seems missing. References. Without references, this is just an opinion.

For example, your meaning of a watt. "A watt is the amount of power that a bulb has and is the measure of energy delivered per unit time." A bulb has no watts, it uses watts. Maybe reference your definition to clarify it.

In regards to a reflector, I don't necessarily disagree with you, but an article should be fact, not opinion. "The best reflectors will have one for each bulb and be parabolic in shape. The closer the shape of the reflector resembles a parabola the better." A parabolic reflector may be the best solution for some style bulbs, but not all. The best MH reflectors are not parabolic reflectors. Look up a Lumenbright, Lumenarc or Lumenmax. Clarify your statement and back it with a reference. Show some PAR numbers of the same bulb using different style reflectors.

My pet peeve. "A major concern with MH is always heat. Since they run so hot fans or in extreme cases chillers are needed to ensure that the water temperatures don’t rise too much during the lighting period." 250w of MH is no hotter than 250w of T5, 250w of PC or 250w of NO. A watt is a watt and it gives off the same amount of heat no matter where it comes from. Put a 250w MH bulb in a sealed box. Put 250w of NO fluorescents in a box. The temp inside both boxes will be the same. If both put out 250w, they put out the same amount of heat. That is a fact!

And as Speed mentioned. "Fluorescent bulbs are best used in more shallow tanks (<20” apporx.) because the lack the intensity to deliver good lighting as tanks get much deeper then that." Not that I totally disagree, but where does that 20" number come from? A reference would legitimize that statement.

I don't mean to rag on you, but IMO if you want to write an article, do so with references to back what you say. You know what they say about opinions. Everybody has 1.............

 

[pat8you]

Without references, this is just an opinion.

I absolutely agree with you. I actually just forgot to add them before i posted this. I have already edited it to include them at the bottom. Here are the sites i pulled most of my information from.

References and links –

Compares natural reef to aquarium lighting
http://web.archive.org/web/20001214154600/http://www.animalnetwork.com/fish2/aqfm/1999/july/features/2/default.asp

Beginners lighting article
Lighting the Reef Tank: A Primer for Beginners by Doug Wojtczak - Reefkeeping.com

Dr fostersmith multiple links on lighting. Very basic but good info
Aquarium Lighting

Scientific experiment of different MH bulbs. A bit technical but informative
http://web.archive.org/web/20001017234419/http://www.animalnetwork.com/fish2/aqfm/1998/nov/features/1/default.asp

Article on Reflectors
http://web.archive.org/web/20010818152111/http://www.animalnetwork.com/fish2/aqfm/1999/nov/features/1/default.asp

Photosynthesis and Photoadaptation
http://web.archive.org/web/20000918065835/http://www.animalnetwork.com/fish2/aqfm/1998/june/features/2/default.asp

 

[pat8you]

A bulb has no watts, it uses watts. Maybe reference your definition to clarify it.

Good catch. Do you think changing "has" to "uses" well be good enough or is a better definition in order?

A parabolic reflector may be the best solution for some style bulbs, but not all.

Thanks i will look into MH reflectors. I don't know a whole lot about them so i have been meaning to do this anyway. After i do some reading i will change this and post the edited version to see what you think.

250w of MH is no hotter than 250w of T5, 250w of PC or 250w

You are correct. I know that watts is just the amount of energy into a system but its usually just so much more of a problem because it concentrates all that energy in such a small area and typically MH set up have more wattage then others. I should and will add your comment about "a watt is a watt" and puts out the same amount of heat but i still feel that a comment should be made that MH set ups should consider ways to deal with heat. Any suggestions on how i can go about this?

And as Speed mentioned.... Not that I totally disagree, but where does that 20" number come from

I really sturggled/debated putting this in there. I'm glad the two of you brought this up. I don't have a specific reference for where i got this number. I have seen it a couple placed for recomndations for the hight but they were all a bit differenet. I just put this down as a starting place. What hight would you suggest. I know there isn't really going to be a "magic" number as speed suggested but i would like to at least give a ball park kind of number so people have an idea of about where it may be better to start looking at other light options. Light intensity follows an inverse square relationship. For example if you double the depth the intensity is reduced by (2^2)4. So where there is no solid number it is definetly a problem that fluorescent lights are going to have trouble in taller tanks because of thier lack of intensity to begin with.

I don't mean to rag on you, but IMO if you want to write an article, do so with references to back what you say. You know what they say about opinions. Everybody has 1.............

Not at all. It was silly of me to forget to put those in before i posted. Your comments are exactly what i'm looking for. Please please continue to rag on me an the article. The more it is scrutinized the better it will be in the end. I'm well aware i don't have all the answers : )

 

[ccCapt]

I don't doubt you researched the info. What I am saying is reference your specific statements. Not just a bunch of links to show a ton of info.

You say "A watt is the amount of power that a bulb has and is the measure of energy delivered per unit time.". Footnote that statement and show the article you pulled it from. When I see a statement I'm not sure about, but see it's footnoted with a reference, it makes the statement more believable.

And I personally wouldn't reference a store that sells aquarium supplies. In fact, the link to Drs. F&S has some very debatable info. They recommend changing a T5 bulb every 16-24 months?

I think you have a good idea, just fine tune it to legitimize it.

 

[ccCapt]

Here's some info to keep you busy for a while.

Spectral Analysis of 175W Metal Halide (Dec 2005)
by SANJAY JOSHI
Advanced Aquarist's Online Magazine - Product Review: Spectral Analysis of 175W Metal Halide

Spectral Analysis of 175W Metal Halide Lamps - Part I (Nov 2005)
by SANJAY JOSHI
Advanced Aquarist's Online Magazine - Feature Article: Spectral Analysis of 175W Metal Halide Lamps - Part I

Underwater Light Field and its Comparison to Metal Halide Lighting (Aug 2005)
by SANJAY JOSHI
Advanced Aquarist's Online Magazine - Feature Article: Underwater Light Field and its Comparison to Metal Halide Lighting

Spectral Analysis of XM 15000K Metal Halide Lamps (Jun 2005)
by SANJAY JOSHI
Advanced Aquarist's Online Magazine - Feature Article: Spectral Analysis of XM 15000K Metal Halide Lamps

Spectral Analysis of Mogul base Coralvue and Coralvue-Reeflux Metal Halide Lamps (May 2005)
by SANJAY JOSHI
Advanced Aquarist's Online Magazine - Feature Article: Spectral Analysis of Mogul base Coralvue and Coralvue-Reeflux Metal Halide Lamps

Spectral Analysis of 250W Mogul base Metal Halide Lamps - Part III:
EVC, Happy Reefing, Agromax and Coralvue (Apr 2005)
by SANJAY JOSHI
Feature Article

Spectral Analysis of 250 Watt Double Ended Metal Halide Lamps and Ballasts
EVC, Happy Reefing, IceCap, AB, and CoralVue (Feb 2005)
by SANJAY JOSHI
Feature Article

More Spectral Analysis of 400W Lamps and Ballasts (Jan 2005)
EVC, Hamilton, Aquaconnect and Helios Lamps and EVC, Blueline, Reef Fanatic and Icecap Ballasts
by SANJAY JOSHI
Feature Article

Analyzing Reflectors: 400W DE Reflectors (Dec 2004)
by SANJAY JOSHI
Feature Article

More Spectral Analysis of 250 Watt Double Ended Metal Halide Lamps and Ballasts (Oct 2004)
by SANJAY JOSHI
Product Review

Spectral Analysis of 400W Double Ended Lamps (Oct 2004)
by SANJAY JOSHI
Product Review

Product review: IceCap/150 HQI (Sep 2004)
by GREG SCHIEMER
Product Review

Thoughts on Reef Aquarium Lighting... Keep Your Eye on the Prize!
by Anthony Calfo
Thoughts on Reef Aquarium Lighting… Keep Your Eye on the Prize! by Anthony Calfo- Reefkeeping.com

Spectral Analysis of 250W Mogul base Metal Halide Lamps - PART II (Aug 2004)
by SANJAY JOSHI
Feature Article

Spectral Analysis of 250W Mogul base Metal Halide Lamps - PART I (Jul 2004)
by SANJAY JOSHI
Feature Article

Too Much Light! (Jul 2004)
by Dana Riddle
Feature Article

PAM Fluorometer Experiments (Jun 2004)
Part I: Effects of Metal Halide Lamp Spectral Qualities on Zooxanthellae Photosynthesis in Photoacclimated Fungia Corals: The Red Light Theory
Part II: Effects of Water Motion on Zooxanthellae Photosynthesis
by Dana Riddle
Feature Article

More Spectral Analysis of 150 Watt Double-Ended Metal Halide Lamps (May 2004)
by SANJAY JOSHI
Feature Article

Analyzing Reflectors: Part III (Mar 2004)
by SANJAY JOSHI and TIMOTHY MARKS
Feature Article

Spectral Analysis of 400W Lamps: XM, Radium, Osram and Sunmaster, PFO (Feb 2004)
by SANJAY JOSHI and TIMOTHY MARKS
Feature Article

SPECTRAL ANALYSIS OF 250W DOUBLE ENDED 10000K METAL HALIDE LAMPS AND BALLASTS (Feb 2004)
by SANJAY JOSHI AND TIMOTHY MARKS
Feature Article

Effects of Narrow Bandwidth Light Sources on Coral Host and Zooxanthellae Pigments (Nov 2003)
by DANA RIDDLE
Feature Article

The Static on Static Lighting: Suggestions for Better Lighting Applications of Photosynthetic Reef Organisms - Moving Light Systems (MLS) (Oct 2003)
by ANTHONY CALFO
Feature Article

LIGHTING IN REEF TANKS: SOME ACTUAL DATA (Aug 2003)
by MIKE KIRDA
Advanced Aquarist Feature Article

Analyzing Reflectors: Part II - Double Ended Lamp Reflectors (Jul 2003)
by SANJAY JOSHI and TIMOTHY MARKS
Advanced Aquarist Feature Article

ANALYZING REFLECTORS: PART I – MOGUL REFLECTORS (Mar 2003)
by SANJAY JOSHI & TIMOTHY MARKS
Advanced Aquarist Feature Article

SPECTRAL ANALYSIS OF 150W DOUBLE ENDED METAL HALIDE LAMPS AND BALLASTS (Nov 2002)
by SANJAY JOSHI, Ph.D. & TIMOTHY MARKS
Advanced Aquarist Feature Article

SPECTRAL ANALYSIS OF RECENT METAL HALIDE LAMPS AND BALLAST COMBINATIONS (Oct 2002)
by SANJAY JOSHI, Ph.D. & TIMOTHY MARKS
Advanced Aquarist Feature Article

Underwater Lighting Conditions (Sep 2002)
by Andrew Trevor-Jones
Underwater Lighting Conditions by Andrew Trevor-Jones - Reefkeeping.com

Metal Halide Lighting Components (June 2002)
by Jon Garner
Metal Halide Lighting Components by Jon Garner - Reefkeeping.com

The Properties of Light
by Andrew Trevor-Jones
Properties of Light by Andrew Trevor-Jones - Reefkeeping.com

Lighting the Reef Aquarium - Spectrum or Intensity? (Feb 2002)
by Dana Riddle and Miguel Olaizola
Advanced Aquarist Feature Article - February 2002

Photosynthesis/Irradiance (P/I) Curves and Why They Are Important to ReefKeepers
by Dana Riddle and Andy Amussen
Reefs.org: Where Reefkeeping Begins on the Internet - Photosynthesis/Irradiance (P/I) Curves and Why They Are Important to ReefKeepers

Lighting the Reef Tank: A Primer for Beginners
by Doug Wojtczak
Lighting the Reef Tank: A Primer for Beginners by Doug Wojtczak - Reefkeeping.com

Spectral Qualities of Various Fluorescent Lamps
by Dana Riddle
http://www.wetwebmedia.com/ca/cav1i4/fluorescent_lamps/fluorescent_lamps.htm

 

[pat8you]

What I am saying is reference your specific statements. Not just a bunch of links to show a ton of info.

Yeah you are probably right. I don't want it to sound like i'm making this all up as i go along. Some of this info like the watt statement you quoted is a summery of a more technical explanation. I'll reference those explanations i guess and hopefully i haven't screwed things up in translation.

And I personally wouldn't reference a store that sells aquarium supplies. In fact, the link to Drs. F&S has some very debatable info. They recommend changing a T5 bulb every 16-24 months?

Yeah probably a good thought. I agree thought that some of their info is a bit iffy. I included it because they also have a lot of very simple info that is good for people just looking to get a quick idea. Maybe just a note in the reference warning that some of it is questionable because they are a retailer or you think just take it out all together?

 

[pat8you]

OHHHH AHHHH that will keep me busy for quite a while. thank you i'll start reading