One important aspect of keeping tropical fish is aquarium lighting. This
is an often overlooked area that can sometimes be confusing for a
beginner to aquariums. The confusion may come from the many available
types of fish tank lighting that you can use to light your tank. The
main types of light are:
- Regular fluorescent lights,
- Compact flourescent,
- High output (ho) flourescent,
- Very high output (vho) flourescent
- Metal halide
- LED - Light Emitting Diodes
The type of light you need for your tank really depends on what you plan
on keeping in your tank. This article is a very general introduction
into aquarium lighting and below we discuss the various types of
lighting needs based on aquarium type. These are general recommendations
and we encourage you to research your livestock's lighting requirements
for best results.
Aquarium Light Types
Regular Flourescent Light
These are the type of lights that come with most starter tanks and are
very affordable. They typically range from 15 to 40 watts and have
Kelvin ratings from 3,000 to 10,000. Kelvin is the scale used to measure
the color temperature. They are very cheap to run and replace.
Compact Flourescent Light Bulb
These are a step up from the regular flourescent lights. They typically
range from 10 to 100 watts and have Kelvin ratings from 5,000 to 10,000.
They offer really bright and intense light but they do put off some
heat that may raise the tank water temperature. Running power compact
lights will require special hoods and because of the heat produced, they
often come with installed fans in the hood.
High Output (HO) Flourescent Light
HO flourescent lights typically range from 20-60 watts and have Kelvin
ratings from 6,000 to 11,000 They are more expensive than regular
flourescents and usually last longer. These lights require a T5 light
Very High Output (VHO) Flourescent Light
VHO flourescent lights typically range from 75-60 watts and have Kelvin
ratings from 10,000 to 20,000. These lights are very expensive and
produce a lot of heat. They require a ballast and/or special fixture
especially for VHO lights. They have fans incorporated into the lighting
unit to help keep the lights and aquarium cool. Even though they come
with fans you may need to equip your tank with an aquarium chiller to
prevent your tank water from overheating.
Metal Halide Light Bulb
Metal Halide lamps typically range from 175-1000 watts and have Kelvin
ratings from 5,000 to 20,000. This type of light is closest to the sun
in terms of luminousity but they are very expensive to buy, operate and
replace. They produce a lot of heat and usually must be fan cooled.
Ballasts with fan units included are widely available. This is often the
preferred method of lighting a reef tank setup with anemones and corals
that need higher intensity lighting.
LED Aquarium Lights
Is this what we have in store for the future of aquarium lighting
systems? Prices as of 2007 are still very high and they will need to
drop significantly in price before more hobbyists will transition to
them. They offer many advantages over previously mentioned lights. Some
of the advantages of LED lights over convential flourescents and metal
LED lights run much cooler than standard flourescents and metal halides
LED lights consume less energy than the other lights
They have a much longer life span
There is no filament to break, so they could be considered more durable
They can be configured in many ways due to their small size.
Many of the light fixtures being sold now include moon lights which are
LEDs. So we're starting to see them more often, but even though these
LED's are very promising we are probably still a few years away from
using them as the primary light source on most home aquariums.
Freshwater Aquarium Light - Fish Only
For a freshwater tank with no live plants you can get by with the low
watt flourescent lights. These lights are typically between 18 and 40
watts and should last for a year or longer before they burn out.
Freshwater Aquarium Plant Lighting
Live plant keepers will need to upgrade their lighting system. The light type you need depends on several factors:
Depth of the tank
Plant species you plan on keeping
Growth rate desired Typically, plant keepers try to provide anywhere
from 2-5 watts per aquarium gallon. Research the plants you want to keep
beforehand to determine if you can provide the light needed.
Saltwater Aquarium Light - Fish Only
Fish only saltwater tanks will work fine with regular flourescent bulbs. Try to get a "full spectrum" light for your tank.
While tanks with live rock can get by with regular flourescent full
spectrum lights they will do better with flourescents and actinic lights
(blue light). It really depends on how well you want the coralline
algae to grow. Certain types of coralline algae seems to grow better
with higher amounts of actinic lighting.
Saltwater Reef Aquarium Light
Saltwater reef tanks with corals, clams and other light needing
organisms will need the high output, very high output flourescent or
metal halide lamps. Certain corals, anemones and clams require very
intense lighting levels that can only be provided with VHO and metal
halide light sources. A general rule of thumb for reef tanks is between 4
and 10 watts per aquarium gallon. Many reefers have lighting systems
incorporating metal halides and VHO flourescent tubes. Research the
species you want to keep because light requirements can vary. Because of
the amount of heat these light units can produce, you may need to get
an aquarium chiller to keep your tank water temperature in an acceptable
range. The expense of lighting a reef tank may be just as high or
higher than the cost of the live rock.
Photo Period - How long do you leave the lights on?
How long should the fish tank lights stay on for? We get this question
frequently. A good range to aim for would be anywhere from 6 to 12
hours. Remember that fish like and need to rest just like other animals.
Fish only setups could range from 6 to 12 hours, reef tank setups and
freshwater planted aquariums could range from 10 to 12 hour photo
periods. Leaving the lights on for longer time periods could contribute
to nuisance algae growth (just one of the factors with algae growth),
higher tank temperatures and quicker tank water evaporation. Be
consistent and if you can afford it, invest in a light timer.
Aquarium Light Timer
You may also want to get an aquarium light timer. A light timer can help
make running an aquarium that much more enjoyable because it's one less
thing you have to mess with. Most higher end fish tank hoods and
fixtures have multiple power cords that are tied into the multiple light
sockets within the hood. This allows you to setup your timer to turn on
the various lights at different times.
For instance, a popular hood nowadays is the compact flourescent hood
incorporating an actinic bulb, a full spectrum bulb and a moon light.
You could set up the timer to turn on the actinic bulb to go on first
and stay on for 12 hours, then have the full spectrum bulb come on an
hour or so later and stay on for 10 hours. This could simulate dawn and
dusk by having the actinic bulbs come on an hour early and stay on an
hour later. Finally, you could have the moon lights turn on when the
actinics turn off. Who knows, you may even start to see breeding
behavior in certain species that may be more in tune with the light of
the moon in this type of setup. Another side benefit of using a moon
light is the super cool effect it creates in the aquarium when all the
other lights in the room are off.
As you can see, the type of light you need really depends on they type
of tank your running. Freshwater and Saltwater fish only tanks can
usually get by with the regular flourescent lights whereas the
freshwater plant keepers and saltwater reef tank keepers will need to
invest in better light sources.