mudplayerx
Active Member
This FAQ and info sheet is mainly for metal halide lighting, but it has some items that are useful enough to categorize it as a general "lighting faq." Please feel free to add anything useful. I take no credit for this information or any of the attachments.
How much lighting do I need?
The amount of light required depends on what type of livestock you want to keep. A very colorful selection of corals can be grown under two VHO fluorescents, or four RO (regular output) fluorescents covering the length of your aquarium. Examples of corals that will do well under this scenario are mushroom anemones, bubble tip anemones, bubble coral, zooanthids, star polyps and other polyp colonies. If you would like a greater variety of species, and possibly a more natural looking aquarium, metal halide or a metal halide/fluorescent combination would be more desirable. Metal halides will give the water column the same glitter effect as the sun, and also enable your system to support higher light loving corals (e.g. most Acropora sp.). As a rough guideline, a low to medium light system uses 2-5 watts of light per gallon, and a medium to high light system uses 5-10 watts per gallon. Corals requiring low light can be kept in high light systems, but may have to be positioned accordingly.
How many metal halides do I need for my sized tank?
The quantity of metal halide bulbs is first determined by applying the "watts per gallon" guideline (see question/answer above), and then by the length of your tank. For evenness of light color across the length of the aqarium, approximately one metal halide per two feet of tank length is suggested. For example, a 55-gallon regular (48" long) could easily accommodate two metal halides, but a 55-gallon hexagon (24" long) would only accommodate one metal halide. If evenness of light is not necessarily required or desired, a 6-foot tank may be maintained with only two metal halides, resulting in "shadier" zones toward the ends.
What is color temperature?
Color temperature, or degrees Kelvin (°K), is a number assigned to a bulb to describe the color of light it emits. The lower the number the warmer or more to the orange/yellow side of the light spectrum is its appearance. The higher the number the cooler or more to the blue side of the light spectrum.
Here are some °K examples and their corresponding color descriptions:
3000K
yellowish
5000K
noon sun
10000K
white with blue
20000K MH
blue
When is supplemental fluorescent lighting desired or needed with metal halides?
Some metal halides produce the proper spectrum of light to stand alone. However, to achieve full enjoyment out of viewing your fish and corals in the colors as they would appear in the ocean at depths of about twenty feet or less, you should use the following guidelines:
5500K MH
supplement with actinic
6500K MH
can stand alone; some actinic enhances spectrum
10000K MH
can stand alone; actinic enhances spectrum
14000K MH
can stand alone; no actinic necessary
20000K MH
supplement with daylight or 50/50
6500K MH Iwasaki
supplement with 3 actinics, 1 daylight for best color
50000K MH Iwasaki Aqua can stand alone />Is heat from lighting detrimental to my aquarium?
Heat is not a problem when using RO fluorescents. When using VHO or MH lighting, however, fans should be installed in your canopy. Chillers are not necessary in most areas, although they are recommended for any system where the air temperature in the room housing your aquarium consistently rises above 90º Fahrenheit. Heater settings may need to be adjusted up when adding a metal halide lighting system in order to narrow the daily temperature fluctuation. Temperatures between 79-84º are OK.
How long should my lights be on?
Guidelines for aquarium lighting photo periods are as follows:
actinics
12 hours per day
MH supplemented with actinics
6-10 hours per day
MH stand alone
12 hours per day
fluorescent systems
12 hours per day
Example times for a three-stage lighting system:
10:00 a.m. actinics on
11:00 a.m. fluorescents on
12:00 p.m. metal halides on
8:00 p.m. metal halides off
9:00 p.m. fluorescents off
10:00 p.m.
actinics off
How long will my bulbs last?
Fluorescent bulbs should be changed every six months, and metal halide bulbs every six to twelve months depending on the bulb type and coral requirements.
Why are compact lights less desireable
There are several reasons why VHO fluorescent tube lighting is recommended over compact fluorescent bulbs. First, compact fluorescent bulb lengths aren't as well suited for most stock aquarium lengths. Secondly, contrary to some posted info, it has found that electronically ballasted VHO bulbs last longer than compacts, and can also be dimmed with an added dimmer. Also, VHO bulbs are less expensive, and the very small output increase that the compact fluorescent bulbs have over VHOs is not significant enough to give up the benefits of VHO lighting.
How much lighting do I need?
The amount of light required depends on what type of livestock you want to keep. A very colorful selection of corals can be grown under two VHO fluorescents, or four RO (regular output) fluorescents covering the length of your aquarium. Examples of corals that will do well under this scenario are mushroom anemones, bubble tip anemones, bubble coral, zooanthids, star polyps and other polyp colonies. If you would like a greater variety of species, and possibly a more natural looking aquarium, metal halide or a metal halide/fluorescent combination would be more desirable. Metal halides will give the water column the same glitter effect as the sun, and also enable your system to support higher light loving corals (e.g. most Acropora sp.). As a rough guideline, a low to medium light system uses 2-5 watts of light per gallon, and a medium to high light system uses 5-10 watts per gallon. Corals requiring low light can be kept in high light systems, but may have to be positioned accordingly.
How many metal halides do I need for my sized tank?
The quantity of metal halide bulbs is first determined by applying the "watts per gallon" guideline (see question/answer above), and then by the length of your tank. For evenness of light color across the length of the aqarium, approximately one metal halide per two feet of tank length is suggested. For example, a 55-gallon regular (48" long) could easily accommodate two metal halides, but a 55-gallon hexagon (24" long) would only accommodate one metal halide. If evenness of light is not necessarily required or desired, a 6-foot tank may be maintained with only two metal halides, resulting in "shadier" zones toward the ends.
What is color temperature?
Color temperature, or degrees Kelvin (°K), is a number assigned to a bulb to describe the color of light it emits. The lower the number the warmer or more to the orange/yellow side of the light spectrum is its appearance. The higher the number the cooler or more to the blue side of the light spectrum.
Here are some °K examples and their corresponding color descriptions:
3000K
yellowish
5000K
noon sun
10000K
white with blue
20000K MH
blue
When is supplemental fluorescent lighting desired or needed with metal halides?
Some metal halides produce the proper spectrum of light to stand alone. However, to achieve full enjoyment out of viewing your fish and corals in the colors as they would appear in the ocean at depths of about twenty feet or less, you should use the following guidelines:
5500K MH
supplement with actinic
6500K MH
can stand alone; some actinic enhances spectrum
10000K MH
can stand alone; actinic enhances spectrum
14000K MH
can stand alone; no actinic necessary
20000K MH
supplement with daylight or 50/50
6500K MH Iwasaki
supplement with 3 actinics, 1 daylight for best color
50000K MH Iwasaki Aqua can stand alone />Is heat from lighting detrimental to my aquarium?
Heat is not a problem when using RO fluorescents. When using VHO or MH lighting, however, fans should be installed in your canopy. Chillers are not necessary in most areas, although they are recommended for any system where the air temperature in the room housing your aquarium consistently rises above 90º Fahrenheit. Heater settings may need to be adjusted up when adding a metal halide lighting system in order to narrow the daily temperature fluctuation. Temperatures between 79-84º are OK.
How long should my lights be on?
Guidelines for aquarium lighting photo periods are as follows:
actinics
12 hours per day
MH supplemented with actinics
6-10 hours per day
MH stand alone
12 hours per day
fluorescent systems
12 hours per day
Example times for a three-stage lighting system:
10:00 a.m. actinics on
11:00 a.m. fluorescents on
12:00 p.m. metal halides on
8:00 p.m. metal halides off
9:00 p.m. fluorescents off
10:00 p.m.
actinics off
How long will my bulbs last?
Fluorescent bulbs should be changed every six months, and metal halide bulbs every six to twelve months depending on the bulb type and coral requirements.
Why are compact lights less desireable
There are several reasons why VHO fluorescent tube lighting is recommended over compact fluorescent bulbs. First, compact fluorescent bulb lengths aren't as well suited for most stock aquarium lengths. Secondly, contrary to some posted info, it has found that electronically ballasted VHO bulbs last longer than compacts, and can also be dimmed with an added dimmer. Also, VHO bulbs are less expensive, and the very small output increase that the compact fluorescent bulbs have over VHOs is not significant enough to give up the benefits of VHO lighting.
