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[APD] Alternatives to watt/gallon rule

Alternative methods to watts per gallon.

There was a mention about using a camera light meter.    A few years ago
there was an article in a FAMA magazine, February 1994 by Pete Mohan titled
"A light measurement in the Marine Aquarium".   He described a method where
a white card of a certain size was put into the bottom of the aquarium at 45
deg and a light measurement was taken off that card with the camera.   He
then provided information how to convert that measurement.   This method
took the measurement at the bottom of the aquarium where you didn't have to
worry about tank depth.

Lux meters.
Here in Australia there is a chain of electronics stores called Dick Smith's
Electronics.   They sell a lux meter for about 150 Aust$.   I used to work
in a public aquarium that had some planted tanks 1100 mm deep and the
Curator wanted to grow water lilies inside.    The wpg rule was a bit hard
to apply so I bought the lux meter then went to various natural locations
where the target species grew and took meter readings thru various times
during the day.    In the shadiest place in the middle of the day we could
find water lilies, the lux meter readings were about 20,000.   We put 3 x
1000 watt MH lights a meter above the 1.1meter deep aquarium and grew lilies
quite well.   The lux meter reading at the waters surface one meter down
under the 1000 watt MH light was about 17,000.   I took lux meter readings
for many of the local aquatic plants in shady areas to work out what their
light requirements might be.   A very interesting project.

I don't think the 1000 watt MH's would be a good idea for everybody as the
electricity bill for the public aquarium was around $75,000 per year.   You
had to swin in the tank to clean the glass and when you stood under the
lights it was a very short time before the steam coming off your head would
have turned to smoke if you didn't move.


On 20/9/05 2:17 AM, "Jerry Baker" <jerry at bakerweb_biz> wrote:

Until I tried it, 
I never believed that some plants can grow more than an inch in a single

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