Crack in glass or ???

[Sablah]

I noticed this today and I'm not sure if its a crack, excess silicone, or what. I don't remember it being there before, but i haven't really looked so it may have been.

This is a picture looking up at the bottom of my tank. Its a glass, 120g with a drilled bottom (drilled on the other end of the tank). I cant feel a crack when I run my fingernail over it.

Is it a crack, silicone, or something else? I tried moving sand out of the way and look from above, but that didn't work out easily, and so I'd rather get an opinion on it before I pull out all my rock and sand to get a good look topside.

 

[Sablah]

Best pictures I could get.

 

[vetteguy53081]

Run your finger nail across it. If you can peel it off, obviously silicone. You can also feel crack if not silicone.

 

[Sablah]

Its completely smooth on the outside bottom. I dont know why I didn't think to feel it from the inside of the tank, ill try that.

 

[Sablah]

False alarm. Its just silicone. Weird that its only on one side of the tank.