Clear silicone turning white in some places, should I be worried?

[AlexS]

My Blau 19L (5G) aquariums bottom silicone seals are turning white in some places. What could be the cause of this and is it going to be a problem?
The tank is only 3 months old

[PB_Smith]

that's normal and nothing to be concerned with.
look at any glass tank that has been up for months and in light and you will see the same.
As far as I know, most silicone with get opaque with age.
What you want to watch for are any areas where it looks as if the silicone is actually lifting off the glass at the edge of the bead, that can be a potential disaster.

Is that a crack/chip in the first pic or air trapped in the silicone bead?
If it's air in the silicone seam, return the tank.

[AlexS]

It must be air because it wasn't there when I first got it and it has never been moved/dropped etc.. Could that turn into a leak?

[PB_Smith]

if it is between the glass and silicone, yes a chance of a leak in the future, but how likely unknown, but I would check it out further for sure.
If it is a new purchase and it's at all feasible you should consider a returning it for a replacement.