Giant bubble in tank silicone

[prisoner1572]

I've had my tank for just over 10 years, and I bought it used at the time. A few months ago I noticed this giant air bubble in the corner. I put a black dot at the bottom of the bubble to see if it was getting longer and it is. I haven't noticed that it is getting wider. I can probably assume that this is a big problem, but I'm wondering how big. Am I pressing my luck by not shutting it down right away? Does it have life left in it? Is it going to blow or will it spring a small leak? It's 125 gallons and it would be a disaster if it was anything more than a small drip since it's in my dining room right now.

 

[Jmunroe]

Looks like the silicone is separating from the glass and the panels are pulling apart. Once the bubble ( which is probably an ingress of water where it has pulled away) gets all the way to the left of the pic at the top it will start to leak there and slowly work it's way down as the bubble continues to hit the outer edge along that seam.