That Garf site is way outdated. It was popular 10+ years ago when the DIY plywood tank craze took off. There have been some successes, but there have been a lot failures following those plans also. When you plug in 25" for height, notice how it says "GARF Does not recommend building a plywood tank longer than 48 inches when the height is more than 24 inches. "
Here you're building an 8 ft tank, at the max height for those plans, using the minimum glass thickness, on a top heavy stand. You might just want to keep this tank in the garage or basement on a concrete floor, where it won't do any damage if it fails. In a living area like in the picture you provided, if you have wood floors underneath that bounce or vibrate, it could be concerning.
Here you're building an 8 ft tank, at the max height for those plans, using the minimum glass thickness, on a top heavy stand. You might just want to keep this tank in the garage or basement on a concrete floor, where it won't do any damage if it fails. In a living area like in the picture you provided, if you have wood floors underneath that bounce or vibrate, it could be concerning.