my 3" crocea clam is pulling away from one end of itself so I can see the white shell. It used to fall over the sides largley and beautiful. I have 3 400W 10K metal halides and 2 72" actinic. I did cut back on my lighting from 8 hours MH to 5-6 hrs due to some algae growth. Could this be the cause? All other water tests are the same as they've always been, my nitrates are at 20 as usual, calcium 420, phosphates are .5 though. I just started testing the phosphate so I can't say if this is how my water has always been or not. I've had the clams for arounds 2 months now, the other is doing fine. One is on the left end and the other in the middle of my tank mid range.