Not sure what a sitroom is but if you are asking about incandescent lights versus fluorescent lights for the tank fixture then I can comment. I personally think the use of fluorescents became popular first of all because they are cooler than incandescents and won't overheat the tank as much during the summer. In addition they are more energy efficient. Lastly, it may be that a majority liked the white light and its effect on fish and plant colors, but this of course varies by individual.
Use of one or the other type of light is still up to the individual aquarist, but I believe the above are pretty good reasons why fluorescents have become the most popular.
~~waterdrop~~