[Matt's Tank]

I was lucky and found a 210 gallon tank on CL for $200. There are two big cracks on the bottom pane. One was fixed with another piece of glass siliconed over it. The other just had silicon smeared on it. Obviously, I'm going to replace that glass. I have the tank mostly taken apart already, but noticed that the bottom pane is 3/4" whereas the rest is 1/2". I plan on going rimless on the bottom so the bottom pane will sit flat on some Styrofoam on the stand.

What is the proper way to calculate the required thickness? 3/4" seems excessively thick. Wouldn't 1/2" work fine since it will be sitting flat?

 

[sohankpatel]

The bottom panes are thicker because I believe that they need to hold the weight of hardscape and substrate, as well as having all the water pressing down on it. I think it is also thicker because it wont crack as easily if you drop a rock or something into the tank. Just a guess.

 

[fietsenrex]

1/2" shouldn't be an issue as long as it sits level and flat.
my 265 gal is constructed completely out of 1/2" but it does have braces at the top of the tank, and the bottom pane is made out of 2 pieces.
the builder of my tank told me that the 2 pieces were to account for any minute twist in the frame which isn't absorbed by the Styrofoam.