Did the math, 613.3lbs empty, not including the top brace. Stand is another 150-200lbs.
When full the whole thing should be roughly:
Tank:613.3lbs
Water:3,242lbs
Sump:294lbs
Water in sump:560.3lbs
Sand in display:650lbs
Sand in RDSB:100lbs
Rough total:5,450lbs
And that's not including pumps, powerheads, additional filters, heaters, lighting, woodwork, plumbing, bracing or tops. So basically it's gonna weigh a little more than a grilled cheese sandwich