Technically correctly assembled panels need nothing more then that paper thin seal of silicone between them. In fact most high-end hand built glass tanks have no inner seal such as the older Oceanic tanks. My 17 year old 120 gal Oceanic has no inside-corner silicone sealed joints. Only the original seals between the overlapping panel is used for a cleaner look and my old Oceanic is still holding water. However if you do get a spot leak between the original panel joints, an inside corner seal will work to seal the leak without dismantling and give insurance against future panel joint leaks. In fact most low-end economy tanks add inside corner seals to insure against leaks in the mass production process. As long as the panel joint leak is not spreading, an inside corner seal is a great fix. However if the silicone between the panels which supports 90% of the structure load that holds the panels together continue to separate in a strait line or unzip, the entire tank could suffer a catastrophic failure where without warning a panel spontaneously separates regardless of new inside corner seals. This is rare but can happen with allot of age, a tank that has been left outside in the sun (UV damage), a tank that has experienced prolong support shifting or stress like on a moving floor (mobile home), or when force moved with significant water remaining in the tank. So if you notice a continued separation of just one panel joint seal longer then 6" especially at the bottom and separation seems to be growing! Better consider a complete panel separation and reseal, rare but it can happen..
