Why are all of my clams dying???

[Nebthet]

Clam deaths seem to be something going on a lot this time of year. I have been hit myself with 2 clam deaths over the last two weeks. Neither of them have had pyramid snails and freshwater dips didn`t help.
It actually looked like something was deteriourating the clam from the foot up. There was no gaping or pinching in the mantle at all, until the day they died where the clam refused to even open and you could see there was something wrong with it.
I had checked all my parameters to see if there was anything in the tank and every thing came out normal.
ammon, nitrite, phosphates = 0
ph = 8.4
alk = 8dkh
salinity = 1.026
nitrates = .05

It sucks, so now I am watching my two remaining clams to see what happens with them.

[cwatkins]

Very strange. Next thing you know hundreds of birds will fall out of the sky and die... Oh wait... Nevermind...