I have a 55 gallon that I bought used. Held water for three months and started leaking. I removed the silicone (looked like it had already been resealed before) and applied a new seal. Tested it and it started leaking again in the same spot. I then noticed it looked like the glass had bulged out ever so slightly on that side. The frame looks fine (no cracks) but would this likely be due to needing a new frame or the sealant not holding? Have resealed a half-dozen tanks and have never ran into this before.