I’m curious how there could be a failure at that area and in that way though? It was 5” up from the bottom on a side panel. Scalloped out and expanding. Just seems like an odd place for a failure to my unless there was maybe a unnoticeable flaw there from the start and that water just caused it to expand and become noticeable. I searched the seams very carefully before I filled it and everything looked good. I was actually pretty impressed with the silicone job. The new tanks silicone is much more sloppy and I had to use a razor blade to clean up a few areas that were smeared all the way up into the viewing area.
Glass breaks from the edge very easily. The panel might have been bumped in that area before it was siliconed by Tim. The defect could have been almost invisible and not prone to break when the tank was unfilled.
When you filled the tank there was quite a bit of stress added to the tank and lucky for you it broke only in a potato-chip, and not the dreaded full panel spider that would have drained the salt water into your home.
That aside, I’m wondering if you were trained in the military? The way you attacked and solved this threat; “Ooh rah!”