There seems to be lot of misconception about Light in Planted Aquariums and otherwise....
This thread is dedicated to Aquatic Photosynthesis which aims to clarify the conception of Photosynthesis under Water and there by help us to choose a suitable light for our planted tanks....
To start off the basic definition of Photosynthesis is as :-
Photosynthesis (Photo = "light," and synthesis = refers to a combination of two or more entities that together form something new ) is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight or artificial light. The food produced from the process of photosynthesis helps the plants grow.
So in Aquatic environment as well it is a similar process the components involved in Photosynthesis are the same with same output except that there are some differences in which aquatic plant Photosynthesis takes place.
Also it is to be stated that Photosynthesis does occur in natural sunlight using the visible light spectrum for the process and same way it also occurs under artificial light using the same visible light spectrum...
to be continued...