I'm so sorry for your losses. We just had a very close experience yesterday morning. Fortunately my wife and I had to cancel a vacation for a family emergency and were sitting on the couch yesterday morning when one of the smoke alarms went off in the house. It took about 10 seconds for us to realize it was the smoke alarm and not a truck backing up on the street.
We have 13 smoke detectors in our house. With a quick rush looking for the beeping we got to my wife's office, where 2 weeks ago we just installed a clown breeding rack for her retirement plan.
Opening the door to the room it was immediate what was occuring the wall under the tank was burning. We are in the middle of a 2 month long retiling project of the downstairs of our home, and everyroom is torn apart. So I had to run to the other side of the house to grab the closest fire extinguisher. Two short blasts and the fire was out.
With the immediate danger over, I was surprised to see the tank was still running.
I had to leave the room because it was filled with smoke.
I came back a few mins later to open the window and get a fan blowing the smoke out.
I was studying the burned area at the outlet, and while I am glancing at it I see a DROP.
After 2 weeks a small drip had started somewhere in the system. A small drip - Like a drip every 20-30 seconds. The water had collected on the middle shelf, filled the shelf and then started to drip out at the lowest point - the middle of the shelf, which just happens to be directly above the outlet. The water was dripping onto a triple plug tap. And the plug tap is what started to burn.
To protect the walls behind the tank from moisture damage I installed sheets of FRP on the wall. It was the FRP that did the major burning.
I used audible GFCI. When they trip they start beeping like a smoke detector. But the GFCI didn't trip and there was still power going to the clown system.
We feel so lucky that we were home, we weren't on vacation, our dogs weren't sitting in the window of my wife's office where they usually sit during the day, that we have smoke detectors in every room, and that we keep (normally) a fire extinguisher next to every tank.
Even with the Extinguisher powder being sprayed onto the fire and into the sump, I am happy to announce this morning that her beginning collection of clowns are all alive and well.
Again, my wife and I are so orry for what you have been thru. We were very lucky. Sadly this is one of those experiences where I don't know what I could have done differently so that it can't happen the same way again. My only thought is to place a water proof cover over the outlet - considering how close it is to the sump, that probably would have bee a brilliant idea.
The 3 Plug Tap that started the fire scorched the GFI, so in the after photo that's a brand new audible GFCI installed.
I hope the recovery of your belongings and getting your house back to normal is as quick and painless as possible.
Best of luck in a quick return back to the hobby.
Dave B