The issue is with this, and I have spoken to Craynerd privately about the matter so I hope he won't mind me airing my views here.
Firstly I've been in the same situation myself as I wanted to get a 90x45x45 rimless, braceless tank made. No tank maker I found would guarantee a tank they made without a brace, so my guess is this guy has said 10mm to ensure the glass does not break. I presume bowing would be an issue on a tank with no bracing, but based on my research I think it's something you can't avoid. I bought a 60x30x35 tank for £25 and removed the glass cover holders on each front and back side of the tank, carefully with a razor and pliers to break the glass lips. After a few hours I had a perfect ADA style rimless braceless tank, and also heavily bleeding fingertips!
Anyway this glass is 4mm thick with a bottom pane thickness of 6mm, the glass does bow quite a bit but does not break when filled. Now witness the recent tour of the ADG showroom in houston on the APC forum, they show you an ADA tank there in detail including the silicone work and construction, this tank also bows slightly. So I think it is something you have to live with.
The issue with the juwel tanks is the black silicone I think looks ugly and I dont like the black trim round the bottom either. Getting a tank made such as this is always a risk as you dont know what kind of a job the guy is going to do with the silicone, the cheap tank I bought when filled with water actually shows air bubbles along the siliconed seams, my thoughts are in time this would lead to the tank bursting.
However what I would do in the situation (and will be doing soon) is ordering one of the braceless rimless tanks from Aquaessentials, these are the same tanks ADA use made by the same people, I think all ADA do is stick a white sticker on the bottom right hand corner of the tank, construction and quality I believe is the same, and the glass thickness quoted on the site matches that of the ADA catalog. For £119 you are going to get a 60cm much better than anything else IMO, I would not bother buying any other UK made tanks and would opt instead for these german ones Aquaessentials has as the price is good and I am pretty sure the quality will be excellent.
what do you mean by rimless braceless? I have been looking to upgrade my tank to this size and i just checked price today, the tank would be £20 and the hood 9.99, the silcone is clear, i have no idea what you mean by rimless though, everything has a rim doesnt it?
observe.....
a juwel tank has some bracing going on, but the rio range have a plastic brace in the middle, sometimes two for the larger tanks....
You notice round the bottom of the juwel tanks there is a plastic trim, this is to hide the thicker bottom glass and also some quite heavy silicone work round the base. This is quite unlike an ADA tank where everything is aimed to be as transparent as possible. I am fast becoming convinced the most important component is the tank itself. But more so the fact that the less visible and noticeable the tank is the more effective.
Welcome to the world of rimless braceless.
