Silicone/aquarium seals?

Tapil

I noticed today on my 2 year old tank that some of the silicone (or whatever that clear glue is) on the corners where the 2 plates of glass meet. is starting to "bubble" and in some areas, tiny pieces are flaking off

Should I be worried?

And if I should what do I do? Is this just extra security or do i need to drain the water and fish and redo the silicone? And how is that done "properly" cause if I have too i was thinking of just going back over the existing

willow

if it's on the inside,then yes,and it needs to dry properly for at least 24 hours.
marine silicon is what i use.