How to prevent Pacman from digging too deep?

[GrifTheGreat]

Hmm seems I can't edit my first post.
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Anywho! Whoop, got to learn about moss in my thread in the vivarium section, moss need's light like any other plant x) Haha, learn something new everyday. Though preventing my pacman from squeaking their feet or rubbing their feet raw against the "bottom" of the habitat still poses as a unsolved problem for me that I will need to answer.

Can't really stop them from wanting to burrow further which is why the frog squeaks on the bottom. Just separate your substrate from the hydroballs or whatever your drainage layer is going to be with a screen. You don't want the drainage layer mixing with the substrate.