humm, a photo of the chip would be nice. That is pretty far through. Also where is the chip located? I have a chip in my AGA 120gal. I did lots of research to find out if it would be alright and here are some of the things I found:
1) if it is a smooth clam shell style chip it most likely will not effect the structural integrity, if it is jagged and has sharp edges it is more likely to effect the structural integrity
2) the closer to the center of the pane of glass it is the better, this way the rest of the glass around it can help hold the chip
Those are the most important parts I can think of right now. But again a photo will help me advise you better.