Hmmm. It isn't April fools day.. I am terribly sorry for your situation. That is a tough site to come home to.
For what it's worth, I have a 480 gallon display that I had custom made some 20 years ago. About 17 years ago, I had check valves keeping my sumps from flooding during power outages... One day I came home to a river running out my driveway and an inch of water throughout my downstairs. The power went out, a check valve failed and my tank was drained leaving all but an inch in the bottom with the fish all struggling on their sides. There was no walking away for me and I went into the panic mode to save the tank. I chalked it up to a learning experience and replumbed the system that day eliminating the need for the check valves. Obviously a different scenario and fortunately, I had the forsight to tile the entire downstairs when I bought my home for this very reason. In my case, the damage was minimal and the tank was back up and running the same day with no fish loss. Thank god for my friend and owner of a nearby LFS as well as my friend Jim who both came immediately with plenty of new water. Now I have keep a couple hundred gallons of RODI and new salt water on hand just in case....
Back in 1994 we had our big Northridge earthquake. I had a 240 gallon tank at the time with a handful of sharks and a 5' moray eel. The quake was so big that the wall swayed enough behind the tank and smacked the return plumbing lines on the back of the tank. They were 3 or 4 inches away. The lines broke draining damn near all the water on the carpeted floor. Fortunately that house was a rental as it made for a real mess. Again, I was able to save all the fish as I had kiddy pools setup in the garage as shark holding tanks as I was importing and reselling exotics at the time. . I fixed the plumbing within a matter of days once the stores like Home Depot and the fish stores were reopened. Again, different scenario.
This is one of those hobbies that is a continual learning experience and every hurdle is a learning experience that when embraced, can make our tanks more future proof and better equipped to insure repeats don't occur. If your issue is a bulkhead seal, that is easily fixed. If your issue is a seam, that's a different story. Still, if you are anything like me and have been in this hobby for the long haul, perhaps this might be a better time to consider an upgrade as opposed to a bail out. Obviously finances and mindset have a big impact on our decisions. Either way, I am sorry for your troubles and I hope the damage to your home as minimal and I hope the livestock faired OK.