How to get assasin snail eggs to hatch?

[Guppy81]

I have currently more than hundred eggs in my aquarium. Those can mostly be found around my homemade lavastone caves, but also inside of Eheim aquaball filter basket. I've noticed that they love to lay their eggs on complex labyrinth kind of surface more likely than solid ones.

So my 6 Anentome helenas seem to be mating a lot and there are a lots of eggs, but I can't see any babies or new adults and it's been over 4 months now. Only fish species I could imagine to eat these newborn babies is Apistogramma cacatuoides, because beside of those I only have Corydoras and Melanoides tuberculata living in the bottom of the aquarium. But I wonder if these eggs have ever hatched at all or even fertilized?

Measured water parameters:
Temperature: 25
GH: 7 dH (could be a little bit higher)
KH: 2 dH (-""-)
NO2: 0,07 mg/l (could be a little bit lower)
NO3: 5 mg/l (good)
Water streaming speed: pretty fast and my filter has bubbling head turned on maximum.

Picture of my assasin snails and their eggs:

[Trillianne]

The babies will burrow for the first few months and you won't see them until they emerge at a bigger size.

[Brhino]

Agree with Trillianne. I got 3 assassin snails for my tank. I never saw any new ones until I tore the tank down several months later to move everything to a larger one. Sifting through the sand I found 4-5 babies. Now I've got dozens of assassins patrolling my tank. I find their eggs on plants and stuff all the time, and they never seem to hatch, but somewhere, lurking in the substrate, there's an assassin snail factory. It just takes a while for them to get going.

[Gogi]

+1 to everyone.

You most likely have babies in your tank already.

[joolzbee]

I'm in the same situation! Started an Assassin only tank months ago...eggs everywhere and lots of enpty egg sacs....must be babies somewhere in the substrate...!