Whenever i add a BTA to my tank, it bleaches out under the halides. I usually put them underneath things, and they come out, and its too bright.
I saw a small holding tank at a public aquarium, maybe 50gal, lit with NO fluorescents, and it was litteraly chock full of BTAs, no surface available, that were all splits from one original.
They certainly DO NOT need MH light, and I think its too strong for most of them.
That being said, certain other anemones (Magnificas, etc) most certainly DO need MH lights.