I also think when there are many many snails , at one point they will regulate themselves by starving ... when an aquarium have more coraline , there are less places to have algaes... when algaes are dominant on the windows , that's where you can see those snails at night.
another thing hapenned to me as close as last week
Ok this one is pretty explicit. 2 days ago I closed my fresh water supply pump. yesterday I come back home to a noisy skimmer pump becose water level was to low , (I think I saved the pump phew) This morning I found my water all smoked up. I can see small particules everywhere in the tank...
www.reef2reef.com
that LOL I gave a description about why I think it hapenned...
couple hours later it was all cleared out so if it hapens at night , I doubt one would notice.
I have no proof or belief that after that , that particular snail died... but again , that could be a possibility.
I know if I did that much ***/body ratio, I would be out of many nutriments and probably lose a couple 10s of pounds lol