I believe it would be safe to remove the top brace seeing that many 30g tanks do not have the braces on top, but don't think it would be a good idea to remove the bottom brace. If it were removed then the 250 pounds of water plus the weight of whatever else is in there would all be on the bottom sheet of glass & I believe that all that stress without the brace would break it, which is most definitely something you do not want. Before you do anything you should definitely wait though for someone else to agree or disagree with me though.