Chase,
Who made the tank? I wish I could chime in here with good news, but at least some manufacturers won't build glass tanks larger than 180 gallons due to seams splitting. What kind of bracing does the tank have? Is it sealed with regular silicone (translucent) or Dow 795 (white or black)? The latter seems to be stronger.
Here is what I wrote about large glass tanks in my Advanced Marine Aquarium Techniques book:
For most homes, the installation of an aquarium larger than 180 gallons will require the assistance of an engineer to measure floor loading, etc. The limit in size for all-glass aquariums seems to be around this volume as well. A pair of 300 gallon all-glass tanks in a pet store would regularly split their seams every two to four years. It seems that there is a point where silicone alone is simply not sufficient to bond panels of glass, even with the addition of corner and center braces. When designing large all-glass aquariums and determining their placement, thought must be given to what happens WHEN their seams will split (not IF).
Jay Hemdal