RE: Lighting

I see this reference to a minimum of 3-4 watts per gallon all of the time 
on all of the lists (Discus-l, Aquarium, and Stripes) and I think it is a 
crock.  Lumens are much more important than wattage, not to mention type of 
plants, and depth of tank.  I prefer Ultra Tri Lux because they are 
extremely bright and my plants grow very well with them at 1.5 watts per 
gallon in a 20L aquarium.  It is 2 15w 18" bulbs with the bulbs overlapping 
in the middle of the tank.  Quality of light and lumen output of bulbs 
should be a much higher concern than wattage.  The bulbs that came with the 
strip lights were only about half as bright as the Ultra Tri Lux bulbs, 
thus I would have to of had 3 watts per gallon if I were going to use 
crappy bulbs.  The other things I credit my plant growth to is the use of 
Kent's Micro Nutrient Supplement and use of a DIY CO2 source if the plant 
growth stalls.

Warwick_d at bls_gov

>up a good portion of the light shining into the tank. The amount of
>plants you can put into a tank (ie. the surface area of plants) is
>roughly proportional to the VOLUME of the tank and this is why we give
>the empirical rule 3-4 watts of fluorescent (or equivalent) lighting
>per gallon of tank capacity as a MINIMUM. With proper precautions for