 |
Intoduction |  |
Lighting Combinations |
 |
Flourescent |  |
Conclusion |
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Metal Halide |  |
Flourescent Cost Guide |
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Spectral Qualities |  |
Metal Halide cost Guide |
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Intensity |  |
Cost Summary |
No subject in reefkeeping has had more debate associated with it, and more words written about it than lighting. Which lighting to use, metal Halide or Fluorescent, was the subject of many heated exchanges in the pages of FAMA, TFH, AFM and MFM. Not only did the debate involve which kind of lighting to use but, in addition, opinions varied on what exact type in each of the available types to prefer and acquire. For instance, when talking about metal halides, the debate was on their Kelvin degree ratings, when talking about fluorescent tube lighting, the debate was on what type and what brand. Needless to say confusion reigned.
Authors like A. Thiel (1985) and John Tullock (1986) spoke out early in favor of Metal Halide forms of lighting and described the benefits of this type of lighting for reef aquariums with photosynthezing corals. Others advocated the use of fluorescent type lighting, with an emphasis on the use of actinic lighting, sometimes suggesting real heavy usage of this type of spectrum. At times the debate was of the yes/no type and, at other times, authors offered choices without stating flat out that their suggestion was the only one that would work and give the kind of results hobbyists were looking for.
All had very valid reasons for their beliefs. As time has passed, newer types of bulbs have been developed, greatly helping the hobbyist to maintain more specialized types of reef aquaria. Examples of this include metal halides with higher Kelvin degree ratings and specialized fluorescent tubes. But, the debate still rages on.......
For a long time fluorescent type bulbs were the staple of aquariun keeping. These bulbs are basically long glass tubes which contain phosphor particles which when an electrical current is passed through the tube, the phosphors heat up and emit visible light. A mix of different types of phosphors will give distinct properties of spectrum and intensity for a given bulb. Fluorescent bulbs come in three types:
Each require different ballasts to start them (listed above according to milliamp ratings) and all have good aplications over marine aquaria.
Metal halide bulbs look like very big incandescent ones. They are high wattage, high intensity discharge tubes encased in a regular bulb looking envelope (although not all of them conform to this description). They heat a metal filament which in turns heat several gases in the core of the bulb producing light and heat energy. A ballast which contains a transformer and an igniter are used to start these lights.
These bulbs produce an intense light that, depending on spectrum, can be near ideal for most reef tanks, especially tanks containing SPS corals. While flourescent light emit light in a linear fashion, metal halides are considered point sources of light and create a strobe-like effect in the water, an effect which many believe is beneficial to the corals. It breaks up light and magnifies portions of it to create natural looking shadows in the aquarium. A similar effect can be created, for hobbyists not using halides, by using a spotlight or incandescent bulb to create a point source of light.
Spectrum is a word every hobbyist has heard in connection with reef lighting. Sunlight is a combination of many types of light blended together. The red , yellow and green areas of the spectrum are the ones most easily visible to the human eye. Ultraviolet, in the blue end of the spectrum, is invisible but its effect can be felt very easily. It is this end of the spectrum that causes sunburn when overexposure occurs. You can usually feel a quick change in temperature of your skin when a cloud passes over. This signals a decrease in the amount of radiation in a given light field. Prolonged exposure to this type of light is dangerous to your skin and your eyes. However UV radiation can also be a driving source in coral health and photosynthesis. Bear in mind that as the depth of the water increases, the red and yellow portions of the spectrum are absorbed and the water appears progressively bluer. This is not so noticeable in our aquaria because we typically do not maintain aquaria with a depth of 5 or more meters (16.5 feet)!
The spectrum of bulbs for aquariums are expressed as a color temperature given or stated in Kelvin degrees. Sunlight has a color temperature of about 5500K, at 12 noon over a tropical reef. Actinic light sources typically have a color temperature of about 7100K. The bluer the light the higher the tempertature. Light is electromagnetic energy in the form of waves. Waves have frequencies. As the temperature of a substance increases, the frequency of the light emitted also increases. Low temperatures produce red and yellow light, while higher temperatures produce light in the blue end of the spectrum.
Light bulbs emitting energy in the 4300 K range are not well suited for coral reef tanks. Too much red light, while improving the look of fish, has been known to stimulate the production of undesirable types of algae, especially when algae nutrients are present in concentrations that are slightly elevated.Wavelengths of light are measured in units called Nanometers or Angstroms. Nanometers are billionths of a meter, while an Angstrom is equal to one tenth of a millimicron. Actinic light sources suitable for aquariums, emit energy in the 420 nanometer range.
How a tanks looks to the eye is expressed as the bulbs' CRI or Color Rendering Index. This, in my opinion, is a more subjective measurement for lights chosen for the marine aquaria. The particular bulbs a hobbyist chooses should have a high CRI number, in the 90's with 95 being a good choice. CRI number of 100 is only possible with natural sunlight. Actinic bulbs, while having the correct spectrum for our aquaria, have a low CRI number. They make your tank too blue, and combinations of Actinic bulbs along with metal halide or full spectrum fluorescent are often recommended to satisfy our aesthetic requirements.
Intensity of light sources is a concept which was new to many hobbyists when reef tanks were first introduced to North America. Aquarists were used to placing just one regular output "full spectrum" fluorescent bulb over a tank and assuming that this was all that was necessary for the animals to do well. Instruments to measure intensity were not a common shelf item in petshops and spec sheets, detailing a bulb's characteristics, were not easily available either.
Intensity is measured as Lux and Lumens. Lumen is the amount of light that falls on one square foot of area with all points one foot from the flame of a candle. One lumen per square foot is equal to one foot candle. Since light spreads outward and scatters in all directions, the farther we are from the source the less light we see. The intensity of light decreases by the square of the distance that area is from the lighting source. If a fluorescent bulb is moved 2 inches away from the water, it will be 4 times lower in intensity.
This is an important fact to remember when placing bulbs that appear at first to have the correct amount of intensity for an aquaria. As you raise them higher above the water, the intensity will drop dramatically and you might not have the correct amount of light reaching your animals.
Lux is a similar meamsurement to a Lumen and is also known as a metercandle in the metric system. One lux is equal to one lumen falling perpendicular to an area of one square meter.
Lighting intensity can be affected by other factors other than distance. Turbidity of the water can significantly reduce the actual amount of light that penetrates the surface and reaches the animals. In tanks where activated carbon is used and is changed regularly light penetration into the aquarium can be maximized. Cleaning or removing glass or acrylic lenses from the light hood will also help. The intensity of light above the surface of a reef can be as high as 130,000 lux. The actual amount of intensity that penetrates the surface of the water can be about 70,000, with maybe only 15,000 lux actually reaching the 10-15 meter mark. The water surface also reflects some of the light back, reducing the amount that penetrates the water and reaches the corals.
Nowadays hobbyists have lux meters available with submersible probes. These are commonly sold by companies that specialize in reef testing equipment. One such company is Ultralife Reef, Inc. of Connecticut. This instrument allows a hobbyist to measure the light intensity in lux over a particular spot in the aquarium, giving the hobbyist the ability to place organisms where they will receive the proper amount of light.
Many different combinations for lighting a reef aquarium exist. The aquarists should first decide which types of animals he or she wishes to keep, and then go about choosing a lighting selection to fulfill their requirements. Keep in mind that you will need to leave room for expansion, or lighting upgrades, should the need arise. Low light requiring animals, such as mushrooms corals or non photosynthetic gorgonians, or corals of the genus _Tubastrea_, will do well under regular output fluorescent bulbs. Two actinic bulbs and two daylights are usually what is required.
If soft corals, like leather corals and some large polyped stony ones, such as Elegance corals are kept, flourescent bulbs of the VHO type are better suited.
Metal Halide are also a good choice for these types of corals.
Careful placement of the organism with respect to the light source and the water motion are important as well, and are often overlooked. Sometimes the orientation angle with respect to the light is the only thing that needs to be changed.
Small polyped stony corals such as _Acropora_ do better if metal halide lighting is used, although I have seen them do well under intense VHO lighting. A color temperature of at least 5500K, but preferably a little higher, such as the newer 6500K and 10,000k bulbs, would be ideal.
I have used the 6500K and 10,000K bulbs over my aquaria and have been pleased with the color rendition and intensity but was not pleased with the performance of the newer 10,000k or 20,000k bulbs with respect to reliabilty. They burn out out more often than not, and sometimes had difficulty igniting. As with anything, a few kinks still need to be worked out with these bulbs before I would rely on them completely.
I am of the opinion that if you can satisfy the intensity and spectrum requirements of the organisms in your tank, then it doesn't matter which particular light source type you choose. The corals have definite requirements in this respect and if you can meet those with fluorescents, metal halides or a combination of both then by all means do so.. You can have great looking aquaria with either of these approaches, as long as you match the requiremts of the animals to the light you choose.
More often than not a mixture of lights will achieve the desired effect. Metal Halides used in combination VHO fluorescent bulbs, is a mixture that has worked well for me and countless others in the hobby. The wattage of the bulbs should be chosen based on the depth of your tank, with 175 watt metal halides being a minimum.
I try to provide at least 3 watts per gallon of light over my aquaria with a maximum of 5 watts per gallon. If the tank is taller than 24 inches then 250 watt bulbs would be better. On extremely tall tanks bulbs of 400 watts are not uncommon.
Remember you can come close to approximating the effect of the sun over a coral reef but natural sunlight is still the best . If my wife would let me I would build a skylight over my tank to let the sun in but as this is not practical I will have to be satisfied with the current lighting I have!
Note on acronyms:
Custom hood made with 4 normal output daylight bulbs and 2 normal output actinic bulbs. Wizard ballasts and BJB endcaps can be replaced with cheaper models. This is assuming you can fit 6 T-12 bulbs into the hood.
Fluorescent Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
3 Wizard Ballasts 28.99 3 86.97
4 Ultralumes 160 10.99 4 43.96
2 Actinics 80 15.99 2 31.98
BJB Endcaps 9 6 54.00
Wiring 15 1 15.00
Hood 40 1 40.00
-----------------------------------------------------------------
Total Wattage 240 Total Cost 271.91
Power Calculations:
Current/Bulb 0.45
#Bulbs 6
Power 324
KwHr 0.324
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 198.68
Replacement Cost/year: 107.92
Total Cost/year: 306.60
Total Cost/Month: 16.55
Note: Replacement costs include replacing the daylight bulbs once a year and the actinic bulbs twice a year. VHO bulbs may need to be replaced on a more regular basis (e.g., twice to three times a year).
Electric/Year = KwHr * Photoperiod * Days * (Cost per KwHr)
Replacement Cost/Year = (# Daylights * Cost) + 2*(# Actinic * Cost)
Custom hood made with 2 very high output daylight bulbs and 2 very high output actinic bulbs. This configuration uses tar ballasts, which will draw more current than shown in the power calculations (due to losses within the transformer), so the power calculations are on the low side.
Fluorescent Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
Tar Ballast 50 2 100.00
4 VHO (50/50) 440 24.99 4 99.96
Wiring 15 1 15.00
BJB Endcaps 9 4 36.00
Hood 40 1 40.00
-----------------------------------------------------------------
Total Wattage 440 Total Cost 290.96
Power Calculations:
Current/Bulb 1.50
#Bulbs 4
Power VHO 720
KwHr 0.72
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 441.50
Replacement Cost/year: 149.94
Total Cost/year: 591.44
Total Cost/Month: 36.79
Custom hood made with 4 very high output daylight bulbs and 2 normal output actinic bulbs. Wizard ballast and BJB endcaps can be replaced with cheaper models. This is assuming you can fit 6 T-12 bulbs into the hood.
Fluorescent Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
Icecap 660 185 1 185.00
4 VHO 440 24.99 4 99.96
Wizard Ballast 28.99 1 28.99
2 Actinics 80 15.99 2 31.98
BJB Endcaps 9 6 54.00
Wiring 15 1 15.00
Hood 40 1 40.00
-----------------------------------------------------------------
Total Wattage 520 Total Cost 454.93
Power Calculations:
Current/Bulb 1.50
#Bulbs 4
Current/Bulb 0.45
#Bulbs 2
Power VHO 720
Power Actinic 108
Total Power 828
KwHr 0.828
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 507.73
Replacement Cost/year: 163.92
Total Cost/year: 671.65
Total Cost/Month: 42.31
Custom hood made with 2 very high output daylight bulbs and 2 very high output actinic bulbs.
Fluorescent Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
Icecap 660 185 1 185.00
4 VHO (50/50) 440 24.99 4 99.96
Wiring 15 1 15.00
BJB Endcaps 9 4 36.00
Hood 40 1 40.00
-----------------------------------------------------------------
Total Wattage 440 Total Cost 375.96
Power Calculations:
Current/Bulb 1.50
#Bulbs 4
Power VHO 720
KwHr 0.72
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 441.50
Replacement Cost/year: 149.94
Total Cost/year: 591.44
Total Cost/Month: 36.79
MH (Pendant) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
Corallife 175W 350 249 2 498.00
2 Actinics 80 15.99 2 31.98
Wizard Ballast 28.99 1 28.99
BJB Endcaps 9 2 18.00
Wiring 15 1 15.00
Hood-ish 25 1 25.00
-----------------------------------------------------------------
Total Wattage 430 Total Cost 616.97
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Current/Bulb 0.45
#Bulbs 2
Power MH 660
Power Actinic 108
Total Power 768
KwHr 0.768
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 470.94
Replacement Cost/year: 173.96
Total Cost/year: 644.90
Total Cost/Month: 39.25
Note: 175 watt matal halide bulbs ideally only draw 1.46 amps from 120 volts. To take into account loss in the ballast, the current is estimated at 2.75 amps. This is a very liberal estimate, so actual operating cost should be much less than shown here.
Replacement costs include replacing the metal halide bulbs once a year and the actinic bulbs twice a year.
2 metal halide lamps with 5500K bulbs. Halides are supplemented with 2 normal output actinic bulbs. This combination utilizes a pre-built metal halide and actinic combination that is not encased in a hood. The hood needs to be custom built.
MH (Combo) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
2 x 175W 350 439.99 1 439.99
2 Actinics 80 15.99 2 31.98
Hood 40 1 40.00
-----------------------------------------------------------------
Total Wattage 430 Total Cost 511.97
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Current/Bulb 0.45
#Bulbs 2
Power MH 660
Power Actinic 108
Total Power 768
KwHr 0.768
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 470.94
Replacement Cost/year: 173.96
Total Cost/year: 644.90
Total Cost/Month: 39.25
2 metal halide lamps with 5500K bulbs. Halides are supplemented with 2 normal output actinic bulbs. This combination is completely do-it-yourself (it does not utilize a pre-built combination). The wizard ballast and BJB endcaps may be replaced with cheaper models.
MH (DIY) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
175 W ballast 60 2 120.00
Mogul base 10 2 20.00
Wiring 35 1 35.00
175W Bulbs 350 55 2 110.00
Wizard Ballast 28.99 1 28.99
2 Actinics 80 15.99 2 31.98
BJB Endcaps 9 2 18.00
Hood 40 1 40.00
-----------------------------------------------------------------
Total Wattage 430 Total Cost 403.97
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Current/Bulb 0.45
#Bulbs 2
Power MH 660
Power Actinic 108
Total Power 768
KwHr 0.768
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 470.94
Replacement Cost/year: 173.96
Total Cost/year: 644.90
Total Cost/Month: 39.25
2 metal halide lamps with 5500K bulbs. Halides are supplemented with 2 normal output actinic bulbs. This combination utilizes a pre-built metal halide base, supplemented with DIY normal output actinic bulbs. The hood needs to be constructed as well. The wizard ballast and BJB endcaps may be replaced with cheaper models.
Metal Halide (2xMH) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
175W 350 349.00 1 349.00
Wizard Ballast 28.99 1 28.99
2 Actinics 80 15.99 2 31.98
BJB Endcaps 9.00 2 18.00
Wiring 15.00 1 15.00
Hood 40.00 1 40.00
-----------------------------------------------------------------
Total Wattage 430 Total Cost 482.97
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Current/Bulb 0.45
#Bulbs 2
Power MH 660
Power Actinic 108
Total Power 768
KwHr 0.768
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 470.94
Replacement Cost/year: 173.96
Total Cost/year: 644.90
Total Cost/Month: 39.25
2 metal halide lamps with 5500K bulbs. Halides are supplemented with 2 normal output actinic bulbs. This combination utilizes a pre-built hood.
Metal Halide (Retail) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
175W 350 599.00 1 599.00
2 Actinics 80 15.99 2 31.98
-----------------------------------------------------------------
Total Wattage 430 Total Cost 630.98
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Current/Bulb 0.45
#Bulbs 2
Power MH 660
Power Actinic 108
Total Power 768
KwHr 0.768
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 470.94
Replacement Cost/year: 173.96
Total Cost/year: 644.90
Total Cost/Month: 39.25
2 metal halide pendants with 5500K bulbs. Halides are not supplemented with actinic (this was not recommended by anyone on the net).
MH (Pendant) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
Corallife 175W 175 249.00 2 498.00
-----------------------------------------------------------------
Total Wattage 350 Total Cost 498.00
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Power 660
KwHr 0.66
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 404.71
Replacement Cost/year: 110.00
Total Cost/year: 514.71
Total Cost/Month: 33.73
2 metal halide pendants with 6500K bulbs. Halides are not supplemented with actinic bulbs.
MH (Pendant) Watts Price/Ea Qnt Subtotal
-----------------------------------------------------------------
Corallife 175W 175 279.00 2 558.00
-----------------------------------------------------------------
Total Wattage 350 Total Cost 558.00
Power Calculations:
Current/Bulb 2.75
#Bulbs 2
Power 660
KwHr 0.66
Photoperiod 14
Days 365
Cost/KwHr 0.12
Cost Calculations:
Electric/year: 404.71
Replacement Cost/year: 180.00
Total Cost/year: 584.71
Total Cost/Month: 33.73
Type Config Total Strtup Elect Repl. Total
Watts Cost Cst/Yr Cst/Yr Cst/Yr
-----------------------------------------------------------------
FL 4+2 H 240 271.91 198.68 107.92 306.60
FL 4+2 H 520 454.93 507.73 163.92 671.65
FL 2+2 H 440 290.96 441.50 149.94 591.44
FL 2+2 H 440 375.96 441.50 149.94 591.44
MH+FL 2 P,2 H 430 616.97 470.94 173.96 644.90
MH+FL 2+2 H 430 511.97 470.94 173.96 644.90
MH+FL 2+2 H 430 403.97 470.94 173.96 644.90
MH+FL 2+2 H 430 482.97 470.94 173.96 644.90
MH+FL 2+2 H 430 630.98 470.94 173.96 644.90
MH 5.5K 2 P 350 498.00 404.71 110.00 514.71
MH 6.5K 2 P 350 558.00 404.71 180.00 584.71
4 + 2 - 4 Daylight and 2 Actinic
2 + 2 - 2 Daylight or Metal Halide and 2 Actinic
P - Pendant
H - Hood mounted lamps
All information presented above was compiled and computed by The Pez. Only public sources of information where used. I can not be held responsible for errors, miscalculations, or changes in prices (ok, maybe I can be, but...).
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