I've had this deresa clam a little over a year now. (I received it from saltwaterfish.com on 9/9/11.) He had been in my 37 under a 150W 14K metal halide supplemented with a single T5HO blue until 9/30/12 when I relocated him to my 75 which is under a 6 bulb T5HO (2 whites, 3 blues, one purple). When I first put him in, my cleaner shrimp hopped on him for a few minutes and seemed to pick at him, but has since left him alone. The clam has been opening up, but there have been two spots on the mantle that haven't looked right pretty much ever since. The spot where the shrimp seemd to pick at him was one spot, which seems to have healed up and looks pretty normal now. At the other spot, one section of the mantle seemed to flip over to the inside of the shell. It's not flipped like that anymore (as of today), but that spot looks a little ragged. I'm somewhat concerned that it might be pinched mantle, but I'm not sure. The arrows in the pics below point to the affected area.
Parameters are as follows:
Temp = 82F
Nitrates = 0 (API Kit)
Nitrites = 0 (API kit)
pH = 8.0 (Salifert kit)
= 8 (API kit)
Specific gravity = 1.024 (Refractometer)
Phosphates = 0 (API kit)
Magnesium = 1160 (Red Sea Pro kit - been working on raising this)
Thanks for any insight you can offer!