Yesterday I noticed that there was a little bit of water pooling up on the ledge of my tank stand. It was on the back edge and not visible from the front or side. Not even sure why I was looking back there but lucky that I spotted it. Once I discovered the issue, i wiped up all the water until it was dry and watched to see where the water was coming from. It was coming over the plastic trim on the bottom back edge of the tank. I believe the bottom/back inside seam had started to fail. I checked the plumbing for overflow and verified everything was dry and no leaks. The tank is 55 gallon drilled with internal overflow box. Made a call to fish den and they had a 55 gallon in stock. Made it there 10 minutes before closing bought the tank and some new sand. Stopped by a friends house to borrow glass hole saws (thanks BrianH!) and made a stop at home depot for paint (for background ) and silicone. Went home, drilled the new tank, and then started emptying old tank into a spare 90 I had laying around. Moved all the coral, rock, fish, etc into 90 and put a heater and power head in there and called it a day. This morning I siliconed the overflow into the new 55 and next step is painting the back of tank. Hoping to have the new tank up and running by end of day.