New Maxima clam gapping??

[bsung413]

Hi guys

I purchased a new maxima clam about a week ago, since then it never fully extend it mantle.

Is it just acclimating into the tank or is it gapping an unhealthy clam?

If it's just acclimating how long does it usually take??

It will react to lighting change (blocking lights with my hand) it's mantle will retreat. Sometime it's inhalant will be open sometimes not.

I have AI SOL BLUE LED for lighting, it's about 16" deep from lighting.

My tank Parameter are
Salinity:1.025
Calcium: 460
PH: 8.1
Alk: 8-9
Ammonia, nitrate, nitrite:0
Phosphate: 0.25-0.5
Temperature: 79-80

Sorry for the bad iPhone picture, don't know how to take a better shot.

Thanks for any comments or suggestion

Berny