To (not) Imitate the Sun
Let's start by putting away the delusion that aquarium lighting is meant to imitate the sun.
Sunlight striking the surface of the sea is intense, continous and almost unidirectional.
Firstly, the intensity of the solar radiation is very high. The average solar irradiation on earth surface is 1380 W/m^2. This means for a 3ft tank, it needs to recieve 566 W of irradiation. If we assume the LED lights are the most efficient ones, (50% efficiency), we need 1332 W worth of light set to power the 3ft tank. Crazy, right?
Secondly, the solae irrad