Glass thickness question, help pls

[rooto56]

So I've been doing lots of research on glass thickness calculators and I keep getting lots of conflicting information, so I came to ask you guys what you think. I'm planning on building a Freshwater Ray tank out of plate glass, and I want to know what thickness of glass is usable, and what bracing should be used. The dimensions I want to build are:
8' x 4' x 2'

 

[pops]

would think 1/2" to 5/8" be fine. nice large center brace a must using the same glass perhaps 1/2 length of tank OC.

 

[boldtogether]

And completly frame the glass...if you want an exposed edge on the glass, you will need much thicker glass....much.
Make the the framing around the glass is adequate as well...I would say no less than 1-11/2" at least.