Please help with fading Maxima Clam mantle

[BleachedCoral]

Hello, I purchased Maxima Clam about 3 weeks ago, and noticed that it's mantle has become flaky and cracked, like asphalt that was heavily salted in the winter (It's more clear when you zoom in on the picture).

It's receiving about 150 PAR and has low to moderate flow. Alkalinity is at 8.2 dkh, Calcium at 480ppm and Magnesium 1400ppm. What could be causing this? It's fading it's beautiful color...

 

[Mr. Mojo Rising]

Personally I would say the par is far too low, I think 350+ is the recommended par for maxima's. Mine is just a few inches under metal hallides. Maxima also does better on a rock than on the sand, maybe move it to a firmer substrate.

 

[shakacuz]

PAR is severely low for the maxima. what is your no3/po4? even though from the picture the tank seems cycled, how old is the tank?