Clam closed up tight

[NoFoolin]

Tank, coral, fish and clam were all looking great before I went on vacation. When I got back a week later everyone survived and I did not observe any ill affects... save for the clam. It is shut tight. The only change I've made recently is dosing Red Sea trace elements A, B, C, & D and Reef Energy A&B in low doses. I performed a water change yesterday but the clam is still not opening up. Does any one have some suggestions?

 

[vetteguy53081]

Obviously, something upset the clam.
Assure none of this occured:
Salinity climbed above 1.026
Temperature is warmer than 80 degrees
Alk is above 9-9.5
Change in water flow
Inside the clam is presence of pyramid snails or a crab
Tank occupant irritating it
Light intensity somewhat low (bulbs starting to dim>)

Pull of on ABCD and use carbon if not already and see if this changes anything

 

[PTXReef]

Obviously, something upset the clam.
Assure none of this occured:
Salinity climbed above 1.026
Temperature is warmer than 80 degrees
Alk is above 9-9.5
Change in water flow
Inside the clam is presence of pyramid snails or a crab
Tank occupant irritating it
Light intensity somewhat low (bulbs starting to dim>)

Pull of on ABCD and use carbon if not already and see if this changes anything

Definitely taking notes, great suggestions :)