Eve, hang on here...

How about this? There's a 215 brick for sale here. No center brace needed, because it's 3/4" glass.

Frankly, I wouldn't panic on yours yet. They've made a zillion of these tanks, with few failures. I'd double or triple up on the shear surface area on the one you have. No, you don't need to drain the tank - you just need to have the dimensions where they need to be - and you can use your old brace as a guide.