[AGA Member] How many wpg is the sunlight?

["Karen Randall" <krandall@rdrcpa.biz>]

Aviel wrote:

>> If I put the aquarium in the middle of the amazon river, and it's day, no
clouds - I get some light intensity over the surface of my tank. Now how
many Fluorescent Watts should I provide to get the same intensity?

I know Lumens and Lux are not the right thing to use but still - I read
somewhere that the sun is 30,000 lux. I think a good 36W T8 Fluorescent is
~2500 lumens. If I have a surface area of the tank of ~1.25 square meter.
Then that's 2000 Lux per Fluorescent. So 30,000 / 2000 = 15 Fluorescents.
Multiplied by 36W gives - 540W and divide it by 200 gallons = 2.7 wpg. <<

Well, there are a couple of ways to approach this question.  I don't think
it is possible to come close to the intensity of full, noonday sun with
fluorescent lighting.

But...

How much light do plants RECEIVE when growing in (any) Amazonian river?

Not nearly as much.

In white water areas, the water is the color and opacity of coffee with
cream.  Light can't penetrate more than a couple of inches.  This is so
marked that white water is substantially COOLER than black water... the
energy (light AND heat) is simply reflected away.

In black water areas, the water is so dark that it's not unusual not to be
able to see your feet when you'r wading.  Not much light getting through
there, either.

There are, of course clear water areas too.  Not surprisingly, these areas
support much more submersed plant growth.  In those areas, however, plants
can be found growing in EXTREME density in water up to 8 feet deep.  Only
the tops of the tallest plants can benefit from the full intensity.

So... You are right, our tanks don't come close to sun-intensity.  But do
our plants need that kind of intensity?  No.  The aquarium plants that are
commercially available are an adaptable lot.  They grow well under a wide
range of conditions or they wouldn't have made it into the hobby.

Karen


 ------------------
 To unsubscribe from this list, please send mail to majordomo@thekrib.com
 with "Unsubscribe aga-member" in the body of the message.  Archives of
 this list can be found at http://lists.thekrib.com/aga-member/