Custom Build Rimless with slight bowing

[dacookster]

Hey folks, I just built my first ever custom rimless, dimensions are 34"w x 20"d x 17"h with 6mm glass(wanted it to fit in a very precise location). Should be around 45 gallons. Anyways, just did its first water test to about an inch from the top and the glass is bowing a bit less than 1/4" in the mmiddle. Is this bowing acceptable toloerance, or should I do a center brace or euro bracing? Any help would be appreciated. Thanks!!