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Re: Light intensity

On Tue, 11 Jul 2000, 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)?

My one "high-balance" tank has 6x32W over a 75 gallon tank = 2.5 wpg,
plus CO2 and fertilizer.  It has heating cables, but they're turned off
because they're too low wattage for the tank.  This tank grows some more
difficult plants like Eusteralis, Eichornia, and some swords.  There are
also some easy plants that flourish in the tank (Java Fern, Anubias).

Various other "low-balance" 10's and 20's have 1-2 bulbs across the top,
meaning 1-2 wpg.  Mostly grow Java Fern and Anubias, though the ones with
more light and some supplemental CO2 are able to support so-called
"medium" plants.  Can't experiment with this now though, because they've
been turned into spawning tanks by my Apistophile wife and I'm not allowed
to mess with them.  They mostly have floating plants like water lettuce
eating up all the nutrients.

I still beleive that the watts per gallon rule is more accurate as a watts
per surface area (as I mentioned about years ago in
http://www.thekrib.com/Plants/Tech/Lighting and in TAG).  For smaller
tanks, you'll need "more" than 2-4 wpg, and larger tanks you'll need
"less" than 2-4.

This was brought rather sharply to my attention when I set up a 45-gallon
"cylinder" tank (I think it was 24" high and 24" diameter) with a 175 watt
pendant light.  All I grew in this tank was algae.  

  - Erik

Erik Olson
erik at thekrib dot com