Some of what I'll write has already been said, so pardon the repetition as I want the "story" to be complete.
First, you do not need so much light. But to understand that, you must decide what type of setup you want. As 1077 I think mentioned, there are many ways to set up a planted tank, each with pro's and (some more than others) con's, and varying in cost to set up and long-term operation costs and maintenance. The method you select will determine some specifics.
The simplest by far method is the one outlined in the 4-part series "A Basic Approach to the Natural Planted Aquarium" at the head of this section of the forum. I won't repeat that here, but it is a low-tech natural approach that I have used for 20 some years, and you can see the results in the photos under "Aquariums" below my name on the left.
Soil is another method, I saw your thread on soil too; and others have mentioned redchigh's series on setting that up. This is also a "low-tech" method.
"High tech" involves more equipment and more maintenance long-term; generally you are adding CO2 diffusion, which means more light and more nutrient fertilization to balance.
Whatever you select, I definitely would replace the white substrate; darker colours (very dark) replicate the natural environment of fish like the tetra you mention, and they tend to be less stressed and thus healthier and more colourful over a dark substrate. And the plants also stand out more.