Bought a tank from a co worker, now im trying to get the crud off the glass. *** noticed there are some bubbles in the silicone bead on the corners. Its a 55G All-Glass tank built in 1987. old owner said it did NOT leak when he took it down. Id like to re-do the corners with new silicone. My main question................can the tank stay assembeled and just trim off the inside edges, or does it have to come apart to get the " sandwich" effect where the two glass panes come together??