i have a 3.5" maxima clam for 4 months now . its been two weeks that his been closed when the lights are on but its open at night . i dont see any snails on the rock or the clam . i oderdosed calcium in the tank , its a 500G . my Cal was around 620 ! i let it deacrease and now its 500 . my clam is doing better and its more open in the day ? is the calcium levels made it close or its the pinch desease . i has gone better since the calcium levels are down . and for some reason i see green hair algae in its big mouth !!!