Clams and Metal Halides

I finally bit the budget and got a metal halide fixture! ;D My fixture has 2 250 watt MH and 4 96 watt actinic lights. I have a dersa and a crocea clam. I am pretty sure it is a crocea clam. Can I put the rock that the crocea is on - on the sand? or does it need to be closer to the top? It is on the sand now, but under the MH. As for the dersa, its on a flat rock that I buried in the sand so that it looks like it is on the sand and it too is under the MH.

Am I doing it right?

 

Congrats! -- nice light system.

Clams should be fine (and do well under them) -- easy to tell if they are happy or not.

 

My fiend keeps his under 400 watts of MH. They look awesome..

 

I have my Clams under 2(250 watt DE HQI's) with great results!
One Crocea is 1/2 way up in my tank with one of my Baby Maxima's, while my large Squamosa, and two other Maxima's are on the bottom in the substrate on a piece of small rock!
You should be fine where you have them!
Good Luck!

 

Granted my tank is shollow in comparison to many, I keep my 2 crocea's on the bottom. I have a 40g 14"in depth. The 150w metal halide sits 6" above the water surface. They are happy as a clam. (pun intended)