DOES ANYONE have a suggestion about HOW to control the Apple snail
population in this Eclipse tank? The problem is the convex and hollow
lid.

FYI, here are two pictures of the female laying an egg sacs on the
inside of the Eclipse lid:

http://phaseportrait.blogspot.com/20...n-mystery.html

I've never seen a picture of apple snails laying eggs. I've found
plenty of pictures of their egg sacs (and them mating), but I've not
found any of them actually laying the eggs.

Perhaps those pictures will help illustrate the problem. It seems like
we need to modify the lid to prevent access to its internals. I don't
want to throw away the tank -- it was given to us by someone who was
too busy to manage it but didn't want to throw it out. Additionally,
because it's an Eclipse tank, throwing it away means throwing away its
filter, pump, bio-wheel, and light (all incorporated into the lid).