Turbo Snails are dying

[lbaskball]

Does anyone know why my Turbo snails show no signs of any activity in my tank? And one died as well. The other type of snails seems to be okay. I just cant figure out what it is. By the way they have plenty of algae to eat. Im thinking maybe it is my lighting? Do I have to acclimate the lighting for these little turbos as well? IF so, why havnt the other type of snails found dead? Please help.
I have a 14gal biocube
150watts of metal halide
Ammonia 0
Nitrite 0
Nitrate 0
Ph 8.1
Salinity 1.024
Temp stay around 79.5 - 80.5
Calcium 420

 

[b.n.g]

i was wondering if u got the chance to acclimateit first b4 u added it to the tank,bcuz when i first got my astreia snails i just added it in there,,the next day all 4 died...im serious...so did u?

 

[d-90]

Are your lights stock? Or did you change them?