more clams dead

[Aquattro]

Jayson, I agred that they need nitrate and yes, there is nitrate in the tank (demonstrated by the fact we see N2 being discharged from the sand). My thoughts are that given the fact we have one or two clams in the tank, the addition of extra nitrate seems overkill. On a farm, however, this may be a different story. The amount of residual NO3 certainly isn't enough to support a huge number of clams in a contained area.
Although I am by far an "expert" on clams, mine do extremely well and have done so over a year now. The growth rate for both my clams is great. I do feed DT's and my clams are over 3", big enough to support themselves via photosysnthesis.
Just the thought of adding NO3 to my tank scares me!!
Pics of your trip to Indo would be awesome.
Thanks for the comments.