WHen I first got my clam it was under a 150 watt halide with a coralife bulb, the bulb was about 10 months old. THe clam is about 4 inches and its matle was about 3 inches wide across sticking out. I recnelty changed the bulb to a new 14k phoenix 150 watt and now the mantle is only about 1 inch wide. I knwo this is becuase the bulb is newer and stronger. My question is what is the proper width the mantle should stick out for a crocea when it has the right amount of light and is not struggling to collect light.