Do you want to do all the seams/seals, or just the inside seams? Not long after I purchased my 120 used, I had a small leak right at the very top of one of the seams. I had just got everything in the tank and arranged the way I wanted it. After debating the issue for a while, and listening to many people tell me to just buy a new tank, I decided to redo all of the inside seams myself with reef safe silicone. I had to move both my rock pillars into large brute garbage cans with PH's and heaters. I couldn't really take them apart. I cut out all the inside seams with a razor, scrapped down to the glass as best I could, and used vinegar to wipe it down (silicone does not bond well to old silicone). I couldn't feel my finger tips for weeks due to the pressure from the razor blade in cutting and scraping. I purchased some additional glass and added some internal bracing in the corners and additional eurobracing along the top of the tank for extra support. It all worked out (knock on wood) but man, what a PITA. Pure reef silicone cures differently than bathroom or kitchen silicone - I taped and quickly realized I needed to get the tape off sooner rather than later to prevent making a mess. Took me a few days and I lost some SPS pieces. Taking it to the next level and doing a complete reseam will involve some large clamps as well as some serious labour and caulking skills. Not for the faint of heart!