This
is the first of a series articles on maintaining planted aquariums.
Lighting is essentially the "engine" of the tank, so we'll
start there.
There are several lighting options available to someone wishing
to grow plants, and I've had experience with most of them. For growing
plants, bulbs in the 5,000 (sunlight) to 6,700 kelvin range are
best in terms of their appropriateness for growing plants. Kelvin
refers to the color temperature of the bulb, which is the balance
of the various wavelengths of light coming from the source. Higher
color temperatures are shifted more toward blue and lower ones more
toward red, with both colors being of prime importance to plants.
A good bulb will have the proper amounts of both. Color temperatures
a little higher than 5000k are fine and give a bit bluer and "crisper"
appearing light. I think they also help many of the feathery stem
plants like Myriophyllum and Cabomba grow more compactly.
10,000k and actinic bulbs are less suitable for aquarium plants
because they lack enough red and other colors, and so should be
avoided. These bulbs are designed for marine applications that contain
algae and invertebrates that need extra blue.
"Cool" and "warm" whites will grow plants but
are far from ideal. In older aquarium literature, you may read about
mixing the two types together to get a proper spectrum, but that
is no longer necessary since more balanced bulbs are now so widely
available.
Normal output fluorescent lighting is what most people start out
with and for many applications is adequate. A general rule of thumb
is 2-3 watts per gallon for this type of lighting if the goal is
to grow plants beyond the very easy Java moss, Java fern, and Anubias.
A good, inexpensive bulb is the GE Chroma 50, which is labeled in
stores as "Sunshine" and comes in an orange sleeve (but
still says Chroma 50 on the bulb itself). It can be difficult to
find these in the 36" length, but 24" and 48" inch
bulbs can be easily found for around $10 or less. This bulb has
an appropriate color spectrum similar to sunlight and is just as
good as much more expensive hobby-oriented bulbs. The Coralife Nutrigrow
is another good one (and curiously the exact same thing as the more
expensive Trichromatic), as is the Triton, although I think the
latter puts out a rather odd pinkish glow (but looks fine when supplemented
with Sunshine bulbs). Most normal output fluorescent bulbs decay
faster than the types to be described below and are good for about
6 months of use, with the Triton lasting about a year. For those
of us wishing not to use carbon dioxide (co2) supplementation, this
type of lighting is the best choice.
Energy efficient T8 bulbs are a step up from normal fluorescent
and an excellent choice for planted aquarium that will satisfy all
but the most light-hungry plants. (T8 refers to the diameter of
the bulbs, which in this case are 1 inch—normal fluorescent
bulbs are T12s). You can get away with somewhat fewer watts per
gallon of T8 light than normal fluorescents.
Energy efficient T8s give out more light than T12s of equivalent
length and last more than a year. Zoomed makes excellent T8 bulbs
designed for growing plants (as does Phillips). I talked to the
manufacturer a while back, and they said that these bulbs are designed
to be run on electronic ballasts, which is what the ones I have
are hooked up to. All fluorescent tubes flicker imperceptibly, but
with electronic ballasts, the flickering is much more rapid and
more light is emitted. Using these ballasts with T8s will make them
last longer, burn brighter, and run cooler. They can be had at electronic
supply stores for around $20 and easily installed.
Power compact fluorescent bulbs are brighter still. They are significantly
brighter than the other fluorescent options and are used for very
light-hungry plants (like Glossostigma and some Myriophyllum species),
deeper tanks, and where there is not room to get enough light from
larger numbers of weaker bulbs. These bulbs are always run on electronic
ballasts. They are very thin fluorescent bulbs bent into a U shape
that plug in on one end only. Unless they are using very little
of it, people using this type of light should be aware that while
PCFs can help create spectacular growth, more attention needs to
be paid to tanks lit by them. PCF tanks will need more nutrients
and co2. Not using co2 supplementation (and I will go as far as
to say a good pressurized system) is asking for trouble. Yeast co2
doesn't cut it in this case. Things go out of balance much more
quickly with light that bright. I am NOT saying that power compact
lighting isn't worth it. It most certainly is. But not for everyone
or every tank.
2 watts per gallon of power compact fluorescent lighting is adequate.
Aquarium Hobbyist Supply sells retrofit kits online that fit into
regular old strip light shells. They come with good electronic ballasts
and a nifty polished aluminum reflector that intensifies the light
quite a bit. A 36", 96 watt PCF bulb (as opposed to a 30 watt
normal output T12 or 25 watt T8 of the same length) kit ran me about
$100. That might sound like a lot, but it's not, especially considering
that the bulbs are good for two years or more. I am quite satisfied
with the kit and the results it provides. Others have had good results
with All Glass units.
Metal halide lighting is roughly on par with power compact in terms
of brightness. A 175 watt pendant will be good for about 2 feet
of tank length. They are quite strong and good for deep tanks (24"
or so). Metal halide is also very expensive, with systems running
several hundred dollars or more. I think that, in most cases, T8s
or PCFs are a better choice.
Incandescent lighting may have been used for plants in the dark
ages of the aquarium hobby, but there are MUCH better options available
now. It takes much more wattage from incandescent light to equal
the light from a fluorescent or halide. The color temperature is
too low (about 3,000) and a lot of energy is wasted as unwanted
heat. Look elsewhere for lighting.
Aquarium lights should be on for about 12 hours per day. Since plants
can't make use of more than that, algae is favored if they are left
on for a longer period. Greater duration does NOT make up for insufficient
intensity. If you don't already have timers for your lights, get
some. It will make your life a lot easier and ensure your plants
get the proper photoperiod every day.
And there you have it. I will of course be willing to answer any
questions if anyone has them. |
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