seams

Hey guys, long time user but created this new account as my old email got lost in a void. I recently bought a 300 gallon glass tank from a local guy in town. Awesome deal on it, and beautiful tank, but it had a problem. Guy said the tank was filled last year up to the 3 overflows with no issues...

So the 400g w/ a steel frame that I picked up has developed 2 small leaks in the bottom of the frame during filling, one somewhere in the bottom lefthand corner and another behind the aquarium also on the left side. I'm draining it now, but removing all the silcone from the tank just isn't a...

I was getting ready to pick up this tank today and it holds water fine. The black silicone seemed to be peeling off the seams. Should I pass on this setup or is that silicone just for show and does not effect the integrity of the tank? Any advice would help I can still go pick it up.