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Re: Light intensity
Subject: Re: Light intensity
George Booth wrote:
>I would like to see a discussion on two topics:
>1) What level of lighting do the experts use (Tom, Roger, Neil, Karen, Erik,
>Diana, Charley, Jon, ... you know who you are)?
>2) Why do many of you think "more is better"? IMHO, more is never better.
>More is trouble. Just enough is better.
I have one perhaps interesting data point to share: I'm just getting
into planted tanks and have set up a 10 gallon to test out some ideas
found in this forum and others (Thanks!). Of course I was so eager to
get the tank going that I planted it before I build the hood. But it
seems to be chugging along fine with DIY CO2 under a 120 watt halogen
Here's the interesting thing: because of the flood reflector, there is
quite a steep fallof in light intensity as you move radially out from
the center of the beam. I can divide the area of the tank into 3
receiving different intensities:
1. The center of the tank gets the best light and has a good crop of
2. The outermost areas of the tank get the least light and have
no algae, but plant growth (and pearling) seems quite a bit slower
than the inner regions.
3. Between regions 1 and 2 there is a ring that is algae free and has
plant growth and pearling equal to or better than region 1 ! This
region is quite clearly deliniated (on the inside) by the end of
algae growth on the gravel (viewed from above, the gravel has a very
clear disk of vibrant green algae in the center).
This seems to indicate that (at least under my water conditions) there
is a small range of light intensities which provide enough for plant
growth but not for algae growth. Or something like that ...
My question: Has anyone experimented with dimming fluorescent ballasts
or whatever to get into this lighting "sweet spot" across the entire
Thanks for listening,
atrom at dnai_com