older 75 gallon tanks built without center brace?

[vincel892]

Is the 1/4" bow including both panels or just one panel?

including both panels
measuring again, width at center without water is 18-1/8", width at center with water is a little less than 18-3/8"

 

[deeda]

Sounds perfectly normal to me, I wouldn't worry about setting it up at all.