There is much more to the lights than the wattage. There is also the "Temperature" of the light, as it is called. Typically this is a number given in K (Kelvin) but specifically it has to do with the frequency of the light. The higher the "temperature" the greater the frequency of the light and the greater energy is puts into the tank. If you are going to use the other bulbs, do some research on the specific nature of the bulb you will be replacing and try to find one that meets it as closely as possible.
"Temperature" of the light - you may have heard of warm bulbs or cool bulbs. Ironically, the warm has a lower "temperature" than the cool. The warm bulbs means that the light is tinted towards the red end of the spectrum. The cool bulbs means that the light is tinted towards the blue end of the spectrum. But, blue light is actually higher energy than red and therefore will have a higher K value.
