I have a bunch of Ricordea's under 250W Metal Halides at sand to mid level and they are doing fine, didn't see any negative effects when I switched from power compacts.
Agreed..bottom half of the tank should be fine for them..just try and find out what lighting they were in prior to your tank and if PC's..place them on the bottom in a slightly shaded area and then begin to acclimate to more intense lighting.