Quote Originally Posted by Jim28fl View Post
I agree with Michael and Philip. normal from manufacture. And if your an experienced reefer. then its likely that this tank last your reef till the seems fail. so buying a used tank shortens the life of the over all system. Hopefully you loose interest n sell it before the tank splits which is the most common case.

I can't imagine buying at 15 yr old tank and setting up a 10,000$ reef in it only to have the seam fail in the middle of the night at yr 17 "2 yrs later" and the whole thing is down the drain. Considering a new tank can be bought for best case scenario 1$ a gallon from all glass. All be it not a fancy tank but still smart money.

Once the "clear" silicon gets really "cloudy" IMO the tank is minimum half thru its life cycle or more. even if it never had water in it. i have heard of some tanks lasting 40 yrs. But not likely.

I also suggest a tile floor…. unless you like dealing with home owners insurance claims..

**a lot of the aquariums have a date to he bottom and the manufacture and also something that says if the bottom glass is tempered or not.
I am not sure any of this answers the OP question but no matter if you buy a new tank or a used tank, every single day shortens the life. It is inevitable that one day the seams will fail. Talking about a 15 year old tank with $10k reef seems pretty extreme though.

My best answer to the OP question is that this was a DIY job (and probably a repair). I don't recall seeing an mfg use two different colored silicone (clear for tank and black for overflow) on one tank.