Just talked to a friend who has experiences with building commercial glass tanks and he does not recommend it. Your tank dimensions (120x70x80 cm, or 48x28x30 inches) will simply have too much pressure on a 10mm (0.4") glass, so he says. He recommends you go at least 15mm.
Required glass thickness is a function of tank depth.
Up to 14" deep use double thick window glass.
From 14" to 18" use 1/4" (6 ml) plate glass.
From 18" to 22" use 3/8" (10 ml) plate glass.
From 22" to 30" use 1/2" (13 ml) plate glass.
