Snails releasing unusual white stuff

[DJKoop]

I've had snails do the same breading show in my tank. There is one thing that went on though that I should have checked further on. Instead of whispes of sperm and eggs I had smalll clouds of sperm and eggs get released from my sand bed about a month ago. I should have dug around to see what was doing it but didn't want to harm anything. Must have been 8 or 10 spots all on the same half of my tank. One started and then they all fired off. It lasted for about 30 secs. Just lucky to have seen it happen.