I kept my squamosa under both PC's and halides, and it does much, much better under halides... although they don't need near as much light as the high-light croceas and maximas, they still like pretty intense lighting.
Also made a huge difference in its color... the colors all deepened and enrichened.
You 'can' successfully keep them under PC's, but like the other clams they do a lot better under intense lighting... just wanted to offer that tidbit.
Be careful of the clam bug... once it bites you it's worse than the reef bug...
