I am in the process of upgrading from a 90 gallon to a 180 gallon. The 180 gallon is a new All-Glass dual megaflow sitting on All-Glass stand. I recently filled the tank to check for leaks, etc. and when I was looking at it tonight I noticed that on the front left seam there seems to be a "line", possibly one continuous air bubble, from the top proceeding down several inches (see pic, tank is dusty from sand that was in it). On the same seam there is the same thing proceeding from the bottom up. It seems to be in the very middle of the silicone seal. The tank was filled with water for several days and I did not notice any leaks. I did notice that the tank was slightly out of level going from fron to back with the front needeing to come up about 1/8" to 1/4" max. My question is "Is this tank safe?" I am being paranoid as it is a lot of weight obviosuly and I do not want any one to get hurt of course. My feeling now is that I should get rid of this tank and stick with my 90 cutting my losses. Or am Ijust being too paranoid. Thanks for your advice in advance!!