Unfortunately, a lot of bowfronts eventually end up failing due to the greater stress on the front glass. One of my customers had an old model all-glass 72 and the entire top brace split right in the middle, causing the glass to pull away from the back wall by about 1/8th of an inch. You could see water through the hole in the brace. I feel they are especially sensitive if you're not 100% careful about leveling the tank prior to filling it.