First and foremost, achievement of a balanced
tank is most important. A balanced tank
can be achieved at both LOW LEVELS of light
and HIGH LEVELS of light.
FACT: A NATURAL AQUARIUM IS A LIFE
SUPPORT PROCESS WHEREIN THE PLANTS AND THE FISH COMPLEMENT
- DURING PERIODS OF NO LIGHT FISH CONSUME
OXYGEN AND RELEASE CARBON DIOXIDE.
- AQUARIUM PLANTS DURING PERIODS OF LIGHT CONSUME
CARBON DIOXIDE AND RELEASE OXYGEN.
THIS PROCESS GOES TO THE BENEFIT OF
THE FISH AND THE PLANTS AND WHEN ALL IS WELL, YOU HAVE WHAT
WE CONSIDER A BALANCED TANK .
THE DEGREE LIGHT AND
LEVEL OF CO2 ARE CRUCIAL FACTORS IN A BALANCED TANK
Light and CO2:
To keep your aquarium plants healthy, the light and
CO2 must be balanced.
- If the light is very intense and there
isn't a corresponding larger amount of CO2, the light
can harm your aquarium plants.
- Too much CO2 without a corresponding
amount of light will affect your aquarium plants ability to photosynthesize,
and can also harm your fish.
- A balanced tank will have more plants
Aquarium plants are grouped in low, moderate and high
light requirements. Plants with low light requirements, such
as Java Fern, Anubias, Cryptocoryne and various water ferns
like Bolbitus Heudelotii, can do well in 1 watt per gallon
or even less. These plants naturally photosynthesize slowly.
(They do however adapt very well to high light levels) There
are also many aquarium plants requiring moderate light levels that
survive just fine in low light conditions. They just grow
slower and less vigorously.
Plants that require moderate light can usually
do well with light levels as low as 1 to 1.5 watts per gallon.
The difference you will find in these lower light levels is
that photosynthesis is slowed, and the aquarium plants grow slower
and less vigorously than they do in higher light levels. Also,
some red plants have a tendency to lose their color.
Strong light levels are considered to be
2.5 to 4 watts per gallon, and there are certain aquarium plants that
require more light to thrive. You will, however, notice a
in the vigor and beauty of all your plants when they are grown
at higher levels of light, but CO2 injection will most likely
So, what I'm trying to say is that you
can have beautiful tanks at low, as well as high levels of
light, through aquarium plant selection and the achievement of a proper
balance between the amount of the light and CO2. (Remember
CO2 levels can be attained naturally through the normal process
of photosynthesis, when we add more light to increase the
photosynthesis process for brighter and more vigorous plants
CO2 injection is usually required to balance the tank).
OH GEEZ you say! How can I handle that? Well,
this is the easy way.
Look at your aquarium plants and fish to see what's happening. If you
notice a problem make an adjustment. There are also test kits
available for this purpose. (Note: last months newsletter
included a chart to measure CO2 levels)
NOT ENOUGH CO2: When there is a deficiency
of CO2 the aquarium plants stay small and grow slowly, sometimes you
will also notice rough deposits on the leaves, this is known
as biogenic decalcification. It could be that you have enough
CO2 in your tank, but you could be allowing it to escape by
over agitating the surface of the water. CO2 escapes the surface
of the water as a gas. So test, and if necessary, turn down
those air stones, make sure that the return on your filter
doesn't splash. If you're running the venturi on your power
heads turn them down or off.
NOTE: It's important to have water movement
in your tank, still water is not good for aquarium plants, just make
sure that it is not over agitating the surface of the water.
TOO MUCH CO2: If you have too much
CO2 in your tank your fish will be at the top gasping for
air. This is caused by oxygen deficiency. READ THIS CAREFULLY:
Deficient light can cause this problem, but; you would
have to be adding CO2 directly to the tank in order for this
to occur as a result of a light deficiency. So please take
this into consideration: In most cases, oxygen deficiency
is caused by inadequate tank maintenance, dirty filters and
too many fish.
You can tell if aquarium plants are photosynthesizing
by observing the plants. When small bubbles form on the leaves
of plants it is a sign that photosynthesis is occurring. Many
hobbyists refer to this as pearling.
What kind of lights should I use over
There are many lights on the market for lighting aquariums.
There are mercury vapor lights, halogen lights, and fluorescent
lights. In most instances the fluorescent lights work the
best. In our opinion halogen lights should be reserved for
very deep tanks, 36in. or more, or used as pendant lights
over open tanks, which is the best use of these bulbs. Mercury
vapor lights are also best suited as pendants over open tank,
but remember, mercury vapor lights are not energy
efficient. Mercury vapor lights also have a lot of the
yellow spectrum, which can create algae problems.
Want to know what makes a fluorescent
light work? Well it's a tube with a partial vacuum inside
and a small amount of mercury vapor. When the light is turned
on the vapor is ionized and gives off ultra violet radiation.
The inside of the tube is coated with phosphor powder; this
powder gives off light when stimulated by the ultra violet
radiation. That is what makes the light. The recipe
for the phosphor powder that coats the inside of the bulb
is what determines the color spectrum of the light.
Here are a couple more definitions you will
Kelvin: This is how the color temperature
is measured; it referred to as degrees Kelvin. It is a measurement
of the warmth of the light. According to this scale 3500 degrees
K would be a warm reddish light; 5000 degrees K would be like
the sun; 6000 degrees K in this scale is much hotter, but
the spectrum is blue which is a little strange to most of
us, but to the scientists out there I'm sure it makes sense.
CRI: This stands for Color Rendering
Index. On a scale of 1 to 100 it tells you how true the illuminated
color of an object is under a particular light. Good aquarium
lights will have a rating of 85 or higher.
Lumens: This is the light output or
Fluorescent lights also come in many flavors.
You can purchase the standard bulbs, VHO (very high output),
or compact fluorescents.
Select a light from 5000 degrees Kelvin, since this color temperature is closest to
equatorial sunlight at noon, to 6700 degrees Kelvin, which we believe looks the best in an aquarium as it is a whiter light and aquarium plants do very well with it. Select a light with the highest
CRI rating you can find, it should be about 85 or better.
Be careful, when you purchase your bulb that
you are buying one designed for aquarium use. Many plant
bulbs or horticultural bulbs are not suited
for aquarium use, first because water filters the color spectrum
and second because they usually only provide the essential
waves required by land plants. Also, their intensity is only
about one-third of that found in a normal fluorescent bulb.
So just make sure that you purchase a high color performance
florescent bulb, and it should say for aquarium use some where
on the packaging. These bulbs are available through many manufacturers
and are not necessarily limited to the ones found in your
local fish store. I've recently noticed that a couple of our
local Home and Garden Stores are now carrying Phillips, Vita,
and Otto Aquarium Lights. Just be sure to purchase an aquarium
light and not a horticultural light.
It will state that it is an aquarium light on the package.
When to replace bulbs:
Usually 50% of the color spectrum is lost at the half-life
of the bulb. So they need to be replaced at that point. This
is usually about every 5 to 6 months for normal fluorescent
bulbs. Compact Fluorescents have longer life and they normally
need to be replaced about every 10-12 months. To your eye
the lamp might look fine, but the diminished color spectrum
can cause the natural biological photoreactions in the aquarium
The difference between fluorescents and compact fluorescents
is the intensity of the light. For example:
Sun Glo Florescent 24 Light 20 watts,
4200 kelvin, 1230 lumens (light intensity)
Power Compact 22 11/16 light, 55 watts,
6700 kelvin, 4230 lumens (light intensity)
Basically, with power compacts you get more
light for the amount of space and connections required. Power
compacts are an excellent choice for planted aquariums. Keep
in mind that you cannot simply replace your normal fluorescents
with these because they require a different ballast and connections.
There are retrofit kits available. Also, aquarium manufacturers,
such as All-Glass are now offering these lights as upgrades.
They also have a compact fluorescent light hood that is sold
as a separate item.
HOW DO I KNOW WHEN MY AQUARIUM PLANTS AREN'T GETTING
THE RIGHT LIGHT?
Here are some good rules of thumb that apply
to light related problems.
Tall leggy plants are a result of lights
with too much red in the light spectrum.
Low, squat growth is the result of too much
blue in the light spectrum.
Stunted growth and normal light deficiency
symptoms described below are caused by too much green and
yellow in the light spectrum.
Symptoms of Insufficient Light: The leaves
are pale green to yellowish, the stems are weak. Stem plants
have few leaves and long internodes; growth near the light
is vigorous and the lower portion of the stem is bare. Rosette
plants have small leaves on weak stems.
The other thing you'll really notice is diatom algae. This
can be caused by several things; not leaving the lights on
long enough each day; lights are old and have lost their spectrum;
algae or calcium build up on the top of your aquarium; too
many floating plants; or, you just don't have enough light.
The deeper light penetrates into water, the
more its' intensity diminishes. There are other factors that
affect lights ability to penetrate water. For instance any
of you who use peat or peat extract, be aware that the brown
color causes the water to absorb a great deal of light, thereby
diminishing the affect of your lights.
I sincerely hope that this information is
helpful. I have many customers that have been under the impression
that if they didn't have 2-3 watts per gallon on their tank
that they couldn't have aquarium plants. Well, that's not true. So
it doesn't matter if you have a state of the art tank with
all the bells and whistles or a gold fish bowl, there are
aquarium plants for you and your fish to enjoy.