NANFA-- lighting
Nicholas J. Zarlinga (njz_at_clevelandmetroparks.com)
Fri, 19 Jan 2001 00:09:05 -0500
Greetings everyone. Your recent discussions on lighting was finally enough
to get this "lurker" to break new ground and put in my three cents. You
all have been such a source of free entertainment for my own version of
voyerism (by listening to all of the wisecracks and squabbles dating back
to before the "taste great, less filling" discussions of Bush and Gore)
that I guess I should give everyone the opportunity to laugh at me! HA!
(that was for Rob) Well here I go. This lighting issue is something dear
to my heart because I have done a bit of research on it. What is basically
boils down to is lots of lighting. Wavelength isn't as important as
intensity. Lots of good points have been touched upon regarding plants in
this discussion. Let me start by saying that tanins can be removed from
the water by the use of carbon or ultraviolet sterilization. The problem
with carbon is that is takes CO2 out of the water which is essential for
the plants to grow. The more light, the more CO2 consumed by plants. If
you have a jacuzzi of air bubbles in your tank, then theoretically plants
don't like that. The calmer the water, the more CO2 is held in the water.
Most plant nuts (no pun inteded) actually add CO2 to the water. Don't
worry, it won't hurt the fish because the water can still hold the same
amount of O2 (which is dependent on temperature). There are a number of
ways to add CO2, whether by a CO2 cylinder or the true aquarist way of a 2L
bottle and some yeast. Also, theoretically, plants do not like water
running past their roots. Their roots should be growing in a nice medium
which is rich in iron. That is why many people use a laterite clay
(originating in the rainforest usually) to add the iron. Trace nutrients
are usually also important too. Of course, it also helps to know what is
actually in your tap water first before you add. That is why many people
use distilled or reverse/osmosis water. This way they start with the basic
water (H20) and can add from there. Now remember when I said intensity was
the only thing important? One thing to remember is that if you use high
intensity full spectrum bulbs, you are adding all of the spectrum which
introduces wavelenghths which are utilized more by blue green algae and
therefore compete with the plants, especially if there are other nutrients
to pollute the water. Using full spectrum bulbs only makes things look
nicer to us, not the plants. Red wavelenghts are used more by plants than
blue. That is why good plant bulbs are a pinkish in color. Also, red
doesn't penetrate the water as deep, therefore more intensity is needed in
deeper tanks. Most plants can grow in minimum light but they get spindly.
When they have lots of light and lots of CO2, they go bonkers! It depends
on what you want. CRI was mentioned. CRI or color rendering index is a
value placed on how close colors look to our eyes compared to sunlight.
Sunlight is 100. Anything close or in the 90's means that objects will
look increasingly more natural the higher the CRI rating. Note that it
doesn't mean that it is a better plant bulb necessarily. As far as T8 or
T12 bulbs, I like T12 because there is more surface area to add color
rendering phosphors in the bulb. (a T8 bulb is eight eights of an inch or
one inch in diameter and a T12 is twelve eighths of an inch or 1.5 inch in
diameter) So, what is the theoretically best set up for live plants? A
thick substrate of fine aquarium gravel laced with an iron containing clay
in a shallow tank with the proper nutrients added to the water (including
CO2) and lots of light on top which is rich in red spectrum. Why do I say
theoretically? Because many people do none of this and still keep plants
alive. Go figure! Thanks for all the past entertainment!
Nick Zarlinga
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"Fish worship...Is it wrong???" (Ray Troll)
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