Quote Originally Posted by 7urb0 View Post
um im not sure where you get this from but the bottom piece should always lay flat on the stand and all side pieces should be built on top.
It's called a "floating glass bottom" and protects against point forces from small debris especially in a frameless tank. It's how my commercial tanks are made as well (though the largest of these I have is 20 gallons). I understand the calculations in the link I gave above give the glass thickness for the bottom piece assuming it is not supported from below, as in the floating approach and/or with a frame. If you can ensure your stand is perfectly level and clean (or use some kind of filler), then I understand the capped approach works too.

I've never made anything this size or to hold this much water, so if you've got information on why the floating approach wouldn't work here with a strong enough bottom pane, I'd love to hear it. I'm sure I've read it's also used in bigger tanks than this, but I could be mistaken.