Maybe I can clear things up a little.
Pinched Mantle is something that has been going around for many years and no one really know what causes it and fresh water dip seems to work in some cases but not all.
About 18 months ago ClamsDirect hired a Marine Lab to test some infected/diseased...
You can do what Russ suggested but I think the best thing is when doing a group buy, let the person that receives the shipment float the bags but DO NOT acclimate the newly arrived animal to that tank. The people that are going to pick up there livestock, do it within hours after the shipment...
It could have been possible a re-acclimation within a short period of time when he received it and then you re-acclimated to your tank. Those small maximas can be a challenge, IME!
Tridacna maxima are by far the hardest to keep IMO and the easiest is the Tridacna derasa.
THANKS FOR THE WARM WELCOME!!
I will be in DC in January doing a speaking engagement to one of the club in that area. We are going to NYC the Wed prior to the DC talk on Sat.