OK, let me try to answer all the questions..
is 7 (NOT 17), That was a typo!
I belive it is a Crocea Clam.
They were both acclimated for 2 hours via Drip acclimation, neither clam was exposed to the air, I transfered them from the bag to the bucket to the tank submurged.
The first clam had been in my tank for about 5 days before I took him back (I wanted to take him back before he died), Within a few hours he was fully open in the LFS
The Second clam is still in my tank today, it has been about 4 days now.
At the LFS
they are in a plastic basket sunk in a shallow coral Vat sort to speak. They are under 14K HQI MH
's at the LFS
I placed the Clams in the middle of the tank, ontop of the sand bed. I tried placing them higher up in the tank on a rock ledge, but by the next morning they end up down on the sand, I'm assuming they are jumping (By Closing their shell quickly).
Again, its a 90g 4' Tank. The Light is a Coralife, uses 2 150w HQI lamps (Which I just replaced last week with 14k Ushio Bulbs), and 2 96w Actinic bulbs which are about 10 months old and are the origional.