I barely avoided a major disaster.....while cleaning my acrylic 500 the other day I noticed a seam that appeared to be separating. It never leaked but didn’t look good. Drained and moved fish but I’m trying to figure out what happened. We had a major power outage a couple days earlier during coldest days of the year and the room temp dropped from 68 to 50ish overnight. The tank water temp only dropped a degree or to, normally 79. Could this cause the seams to fail? And can it be repaired? The pics show a piece of paper slid into the seam after it was drained.