Yea I agree. Im sure they know what they are doing but a few things I see.
1. No cross members on the top. This is a 4' tank.
2. Its a solid glass bottom not rimmed. Where is the support for the glass not supported by the edge? A rimmed tank would be fine but?
3. You will have a huge amount of light into the sump with no bottom.
A piece of plywood or pvc for a top would supply needed support I would think.
Here is my 120 welded stand which is the same dimentions. It required top cross support and 3x2 top and 2x2 side and bottom for structual integrity.
No bottom support needed but I made a floor so nothing sat on the ground.
I just saw the length wise support.
Anyway not trying to rain on your parade just concerned as I have never seen a stand built that way.
If you are running a sand bottom it will be ok unless you run a light to your fuge.