One of the Reasons I Don't have a Sump

[ron101]

as for the thread, bad choice of where to drill it coupled with an unsupported bottom. all that don't support a tank with trim is bunk if you use a foam that will take out the irregularities it only adds to the strength and resistance to cracking.

Those are my thoughts as well. Regardless of how the connections are configured, the bottom pane supports the vertical load and the sides hold the water laterally. I can't see how a foam insert below the bottom pane would not be a benefit. What is supposedly happening with the forces in the opposite scenario?

But yeah, just about the worst place to drill the bottom pane, right in the middle...