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How Much Light in an Aquarium?: |
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All I Need to Do is Stick in a Normal
Bulb, Right?
Wrong! Unfortunately, nothing is that simple. First off, when choosing
your hood, you need to decide between an incandescent hood and a
fluorescent hood. Most large aquariums (10 gallons and above --
the sizes you should be keeping goldfish in) come with fluorescent
lighting fixtures. While that may have made the choice for you,
it's still nice to know why
fluorescence are preferred in the aquaria-keeping hobby.
Incandescent bulbs may be cheaper off the shelf, but they will actually
end up being more expensive in the long run. They last for a much
shorter time than fluorescent lights; there's also the risk of the
glass breaking. They use more energy for the same output of light
as a fluorescent bulb, as well. Incandescent bulbs also give off
a lot of heat, which can heat the water of your tank, and while
they give off heat, they don't give off the wavelengths that the
fish (and plants, if you have any) need.
So, what is light and wavelengths, and how do they help? Light is
generally considered to be the visible (what we can see) portion
of the electromagnetic radiation (EMR) spectrum and wavelengths
are the distance between the crests of the waves light gives off.
Visible light as measured by this unit of length is 400 to 700 nanometers
(NM) (1 nanometer = 0.000,000,001 meters). To the left of this chart
is the invisible light (at 380 NM), which includes ultraviolet radiation,
gamma rays, x-rays, etc. On the right of the chart is the electromagnetic
radiation wavelengths that are greater than visible light (780+
NM), and includes Infrared, microwave, television, FM/AM, etc.
Since a lot of light, when hitting a denser medium such as water,
gets bounced off or absorbed, it is important that the light is
strong enough to reach organisms that need it, such as fish and
plants.
However, too much light can also be harmful to fish and plant alike.
A light schedule must be kept in mind: fish/plants from colder climates
do not experience long daylight hours in their natural habitat and
will not respond kindly to intense lighting for long periods of
time.
all right, so incandescent bulbs are out, but what about fluorescence?
They're an inexpensive alternative, come easily available, and have
many varieties -- too many. Robert Fenner,
from Wet Web Media, suggests a few fluorescent bulbs and mentions
a few things to be on the lookout for:
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