Bubbles in silicone, cause for concern?

[Alexraptor]

I have a custom 38 gallon tank that is about 20 years old, and I noticed some air bubbles/pockets inside the silicone today, near the top of the tank.

Is this cause for concern? is this the beginning of seam separation, or just something I should keep my eye on?

Here's a macro shot of the entire affected area. (NOTE: Ignore the huge splotch near the top, thats just salt splatter!).

 

[TX_REEF]

Given the age of the tank, I would plan a replacement/upgrade. It might be fine, it might not - and if it fails, it's a safe bet it'll happen when you're not home unless you have eyes on the tank constantly.