Tank issue - Anybody seen this before?

[Stussi613]

I sold my 60g tank yesterday and the new owner was filling it up when a white line appeared in one of the seams. Silicone is perfectly intact and I've never seen this type of thing before. Only appears when the tank is 3/4 full if perfectly level, otherwise it's the usual black joint. Anybody know what it is?  Is it a stress issue?  Will it compromise the integrity of the tank?  i.e. Will the seal eventually weaken to a catastrophic failure?

[Nerine]

my 55 does the same thing...I honestly don't know LOL I never really bothered with it before! I know that the excess silicone does seep out a bit between the joints and has turned white (it has done it with a 20 I have)

but you had the tank filled up before? they didn't bang it against anything?

I'd let it sit 48 hrs with water in it, checking it often...my two cents

[Stussi613]

The tank was full for six months in the last stint as a tetra grow out tank, but I never noticed it...it may very well have been on the back of the tank, to be honest. I was told by the new owner that they didn't bang it into anything, and I believe them. Not asking for their money back, just worried it's going to spring a leak. 

[Nerine]

I don't think so...but maybe someone else will chime in???

[bitterman]

It is possible the tank got bumped in the move? Also could be the new location were the tank is sitting is not in a perfect plain (Top of stand could be twisted slightly) This would result in extra stress on the seams and in turn could result in the tank failing. But I am not sure if that is what is being seen here.

Good luck,
    Bruce