Very interesting.. I sometimes put my old corallife fixture on the back of my tank which had 2 lights, only about a 3 inch wide fixture and the bulbs put out about 21 watts each..
Anyway, almost as soon as i put that on 5 minutes later the plants start pearling too..
Ive now switched those bulbs to my T5HO fixture and they are Fulham 39w T5HO's, yet i cannot find a spectrum for output for those bulbs anywhere on the internet...
If you are feeling froggy and wanna try looking for that id be in debt to u! lol