They don't always sink right away, takes awhile sometimes (as in quite a few hours). I haven't had any that wouldn't sink after 12 hours but maybe at that point it might be a sign that it not mature, and I have had some that popped and some that didn't out of the ones I have tried to germinate.
Ok thanks for the reassurance guys ill see what happens with it Can you tell if it'll sprout after the initial 16 hrs in water.... then i am doing paper towel method