I tend to think that tank leaks/failures are mostly caused by the owner not the manufacture.
The manufacturers follow the same basic assembly process and use the same basic materials: glass, silicon glue, center brace if span is greater than 36 inches, plastic trim, etc. The primary difference between the high and low cost tanks is the optical quality of the glass, the thickness, at what size tank they start using tempered glass bottoms, the edge finish, and the neatness of the glue bead.
I believe if we set up 75G tanks from all the manufacturers; carefully placed them on perfectly level stands with foam between the tank and stand; fill them with water and leave them unattended; they would all hold waters for years & years.
Now factor in the human element:
- The banging, twisting, and grabbing of the center brace as we move it from the store to the stand at home,
- We use a stand that's not perfectly square and warps over time, a floor that is not level and changes over time (settling, seasonal warping, carpet compresses, etc)
- We drop a rock or two on the bottom as we initially decorate or during one of the hundreds of tank cleanings.
- We damage some of the silicon when we scrap off the algae in the corners.
- During a party, or when the kids are in the room unattended, someone backs into the tank hard and causes it to distort slightly.
So to sum up my point: It's not the quality of the tank that matters; it's the care of the owner....... a higher quality tank is just more forgiving of a careless owner.
I consider myself a careful owner, yet I have a 75G Top Fin tank that may spring a leak due to my poor installation. I was so careful measuring the slope of my carpeted cement basement floor, and perfectly cutting two 48 inch long shims that go from paper thin to 3/4 inch. What I didn't anticipate was that the slope was not uniform and the carpet padding covered that unevenness up. Now after a year, the carpet padding has compressed opening up a 1/32 inch gap between the center of the tank and stand. The tank is basically being supported by the ends. If the tank had sprung a leak, and I had not noticed the gap, I would have blamed Top Fin for making a low quality tank.