I just read in Amano's Aquarium Plant Paradise that changing the light spectrum will cause leaves great distress, the plant will have to shed the old leaves and grow new ones to effectively use the different spectrum.....?
This agrees with my observations of a change in lighting creating algae on all existing leaves but new leaves are just fine. I saw this when I went from dual flourescets to 55 watt PC in the 20 gallon. Now those same plants are moved to another tank, with 55 watt PCs of different spectrums and I am seeing algae on old leaves, not new.
In a new tank, they say you just have to wait out some of this. Best thing to do, if this comment by Amano is correct, is to get the plants growing ASAP, then cut off the old leaves.