Yes, I think the 10mm glass is the weak point, but not necessarily a fatal flaw. I'm sure there are a couple of tank building sites that offer glass thickness calculations. You may be fine with the 10mm front glass, especially with euro bracing at the top and bottom. The water in your tank is going to weigh about 1000 pounds (450 kilos). So the question is, can 10mm glass at 5 feet long hold up to 1000 pounds of pressure. I think doing a double bottom makes a big difference, but again, I'm no expert.
I'm a bit surprised Uncleof6 hasn't weighed into this thread. He is much more knowledgeable about this than me... and probably WAY more conservative on the side of safety. You might want to send him a PM and get him involved.
I don't usually check what is going on out here; and yes I am a bit on the conservative side when it comes to safety. To give it some perspective:
It would be nice if, when running the algorithm, it would come up "even" and say 9mm, 10mm, 12mm, 15mm depending (standard glass thickneses.) More often than not, it falls inbetween. It becomes a question of how far from the lower or higher thickness does it fall, and then after that is the question of the experience of the builder.
Very experienced, go down, but then someone with sufficient experience won't usually be asking about glass thickness; and if little to no experience go up. Manufacturers will invariably go down and then some; and custom builders will go up or down, depending on things like shipping. With custom builders and manufacturers, the consumer can usually "rest easy" because the liability is on the builder, not them, provided they follow the builders recommendations concerning stands etc.
We have two safety factor points: 3.8 for a full metal rim (manufacturers excluded) and 7.6 for a rimless tank. For a tank with additional bracing: 7.6 SF less 1 standard thickness down, will usually be safe. The bottom of the tank needs to be dealt with as a rimless tank would be. Of course nothing ever comes out even... so invariably we are always inbetween...
On the pressure: call it 125 gallons with a weight of 1072lbs. The stand carries the load. (or the bottom glass panel with a full floated bottom, and the stand.) The pressure at a depth of 20" is 15.442psi. Does not seem like much, but it will push the side glass out (14.8psi will push the glass out; atmospheric pressure is 14.7psi at sea level) and if the glass is not thick enough, the seams will pop. So glass thickness is about reducing the outward deflection as much as possible. So sometimes it is a judgement call based on how much tolerance for deflection the builder has.
You have an interest in tank building, so this is offered for consideration.
