[George]

I would be more worry about your clams than your corals. Many fish (for some reason angelfish are notorious for that) are attracted to anything that comes out of excurrent siphon of a clam, be it poop, un-digestable food or zoox (sometime a clam can expel zoox for various reasons). When a fish picks at those things, they annoy the clam and the clam will close. Clams can be harassed to death by this action. This is the major reason I don't keep clams in my angel fish dominated reef tank.