Do you think this will harm the clam as to not getting enough light during acclimation?
Assuming it was healthy when you added the lights, it looks more like the result of TOO MUCH light IMO
. The way it is pulling from the shell suggest major stress. Too little light would not cause that to happen so quickly IME
. Remember, it's the intensity not "brightness" of MH
that separates it from other light sources. While it may look dim to you, the corals will really feel the difference.