Not Good!

[Marlin65]

Does not look that bad I would patch it.
If you put the patch on the outside you will hardly be able to tell.
The crack is not structural and it is all the way through looking at the picture.

[Todd]

Manufacturer should replace or repair it. The break is from using glass that is too thin for that structure. Regardless of it it had a wavemaker on it or not, the tank should be able to handle it. If it was something you designed and had built, then the manufacturer should have told you this would be an issue, or too bump up the glass thickness and include that in the price.

[chevyjaxon]

OUCH I know how that feels i once had a 55 gallon where the glass on the front pane broke near the bottom not fun it took me 3 years to get over it and buy a new tank to try again i feel for you