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Re: The "Watts-per-gallon" Survey finished

>From: Erik Olson <eriko at wrq_com>
>Subject: The "Watts-per-gallon" Survey finished

I really like your lighting analysis. Very thought provoking. You have
clearly shown that Amano's data conforms to a watts per area formula.

I used to think that one of my large tank data points was a clear outlier:
80w per 280L. Now I see it fits nicely into Amano's data set. Same for the
other two higher light tanks: 160w per 300L and  280w per 500 L. This may
add more "ammo" to the argument that some people are using more light than
they need. 

However, another variable which probably needs to be considered is general
hardness and other water chemistry parameters. My water is very soft
(20-40ppm Ca). Some people say that they can't grow plants at my (or
Amano's) watttages. It would be interesting to stratify your data into the
lowest and highest quartiles of wattage per area and then find out if there
are systematic differences in the type of water that people have.

Another small point, not related to your general conclusions: In the
article you say "incandescent light, however, is about 1/4 as efficient as
flourescent." Although incandescent may be 1/4 as efficient in the spectrum
used by the human eye, is it the same for plants (i.e. considering PAR)....
Incandescent is  heavily weighted towards the red and far red which we
can't see, but plants can use and enjoy.

Thanks for making an important contribution to aquatic gardening.

Neil Frank, AGA