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Re: [APD] light and the w/gal rule

S. Hieber wrote:
> How much light do you need on your porch? About 15 watts
> fluorescent or about 40-60 incandescent.  Could a finer
> prescription be develooped? Sure. Would we have better
> porches? Generally not, imo.

This is a good example, and one that a lot of people should keep in 
mind. However, what is driving me is the curiosity about what light 
levels accomplish what. How much PAR is required to get the internodal 
length in Ludwigia glandulosa under 50mm? At what PAR levels does Rotala 
indica turn red? What PAR will keep pygmy chain swords under X height? 
That kind of thing.

Sure, we can all put some reasonable amount of light over the tank, and 
even balance light levels by adjusting the photoperiod, but that doesn't 
give us any hard data. Hard data are not required if you just want to 
throw some plants in the tank and have them survive, but hard data is 
required to understand and predict the behavior of plants in the 
aquarium. Even if the end result is to say that watts per gallon is a 
good rule of thumb, it still needs to be backed up with data other than 
anecdotal evidence in order to have any real meaning.

Jerry Baker
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com