maxima clam central bleaching

[douglam]

I had 4 maxima clams 3 that are about 2 inchs and 1 that is 3 to 3.5 inches. i was just home for 6 days. i left the tank under my roomates care, he has a reef tank at home so hes qualified. when i came back on the 6th night one of the small clams was dead and being picked clean by my shrimp and crabs. the other three looked totally fine, it was dark in the tank mind you. the next morning i noticed that the larger clam was slightly bleached in the center. i honestly dont know if it was like that when i got it but i dont think it was.

 

all my water params were fine except maybe my salinity being a little high because my Top off water ran out while i was gone. (MY FAULT) the salinity had risen about .03ppm to maybe 1.027 or 1.028. I usually keep it around 1.024 or 1.025.

 

The two small maximas are fully open and look great, except on of them also has a slightly bleached center, this one was like that when i got it though, it has not gotten any worse, might actually be better.

 

all three clams are in my 12 G aquapod, on the sand bed directly underneath my 70 watt halide. the halide is on the front of the tank and i have the 40 watt nova extreme on the back of the tank. I believe this should be enough light.

 

I think the big on that i noticed the bleaching on was under a brighter light at the LFS and was closer to the surface.

 

ANY IDEA WHAT COULD BE GOING ON? OR HOW TO HELP THE CLAM GET BACK COLOR?

What generally causes a clam to bleach in the center.

[disaster999]

wow...4 clams in a 12g...you keep up with dosing calc?

[douglam]

Three now but I haven't changes my dosing and haven't noticed a fluctuation in calcium consumption.