Building an aquarium

[Jayw78]

Hi guys just need a bit of advice I'm toying with the idea off building a 3.5 foot drop off was thinking of 12mm glass double base with a 2.5 to 3 ft drop off any advice if the thickness of glass would be right also would I have to brace any help would be great

 

[Mandelstam]

I've never built one so this is just some quick thoughts.
A drop off tank has a lot more going on in terms of forces and construction than a standard glass box. So a lot of research and planning is necessary.
Do you have any plans or drawings you can show? I think it's easier to give input on an actual sketch than just a quick description. Do you plan on using full sides with floating top bottom or L-shaped sides? To me full sides seem to have a few advantages in terms of ease of build and less complex stand.