I think kmarch is right. I'd even go a bit further and say that they are not good for Phals. either
Are you using the 24" ones or the 36" ones? Are they behind protective crystals (splash guards)?. If they are they will act as filters too.I did have them for my aquariums but they are expensive to replace ($22.00CAD each). They are very good for aquarium plants (and for fish-colour) but I am not sure if they are OK for any other plants( except may be mushrooms).
I am afraid you cannot use them for any orchids by themselves. It would be very useful if you can add an additional lighting (twin) with a 'daylight' bulb($5.00CAD) and a 'broadspectrum' light ($8.00CAD). You will see a world of a difference when you do that.
Good luck.