Ok I wont touch the mouth at all. Its currently sitting in the middle of the tank is 2" or a bit more of sand with its base along some rock. Always seems to back itself in. Medium flow. I will stay on top of water changes, my skimmer just stopped working this weekend actually. Debating whether to get another one or wait until I upgrade the tank.
What do you think about something odd happening like something falling in and it cannot get it out?