i'd say 9 or 12mm sides and a 12 or 16mm bottom with a very strong sheet (3/4") of plywood underneath. Thicker glass also provides more surface area for the silicone, allowing a better margin of error in case one makes a boo-boo.
when you increase both your distance side to side and front to back, you need a thicker glass because even though there's head pressure pushing to the sides, there is still a lot of pressure going straight down. The sides are keeping the water in the tank, thus causing gravity to push all the water down.
better safe than sorry
__________________
Everything I put in my tank is fully dependant on me.
|