90 gallon question

[fatboy8]

Just picked up a 90 gallon tank and took notice to no center brace. The glass is 1/2" thick and am wondering if I should consider the brace. Second it came with no lid and it seems you cant find one now that isnt built for tanks with braces. Any suggestions?

 

[Drstrangelove]

You should only need 10mm glass on a 90 (48x18x25), but if it's 1/2", then you have 12.7mm, so you are probably fine without a brace. 12.7MM is roughly 4.4 safety factor. Best thing to do is fill it and measure the bowing which should be no more than .33MM.

If you are getting much more (e.g., if it's approaching .75mm bowing as the water nears the top), then you will want a brace.

Many tanks are built lacking a brace by using thicker glass.