We had a disaster happen several summers ago when the power went out while we were on vacation and it was over 100 deg. We had a house sitter, we had a gennie with extra gas and spark plugs on the patio. We had a stack of extension cords with labels on each end and a map to where they needed to go.
But the power went out while the house sitter was at work. We had a 400g display tank at the time. And the fish loss was well into 5 figures.
We got home and 4 days later I found a used low hour Generac on Craigslist. Hired a solar installer to wire it to the house with an fully automatic transfer switch. It's a dual fuel, so it will run off propane or natural gas. It's normally hooked up to Natural, but flip a switch and move 2 valves and it is hooked up in 30 secs to a 300lb propane tank.
Total cost of Gennie and install was less than 5g. Value of piece of mind --- No price on that. In the event the power goes out the whole house is powered back up in under 20 seconds - whether anyone is home or not.
We have a 26k Generac with the Generac ATS - It will support our entire house (3k sq ft), guest house, multiple multi ton AC units and the 1500g system without any issue. All without any involvement from me.
The generator runs every Friday night for 10 mins and then sends me a text that is working and ready to go. When the power does go out the generator has it's own 5g signal and texts me that the generator is running and texts me again when the power comes back on.
You don't have to have a huge tank to have a 4 or 5 figure investment in livestock. So the investment in a whole house generator to protect your investment in the livestock really isn't that much of a big deal. And if you have a 180g+ and don't have a gennie ready to go.... Then you know you've already prepared yourself for an upcoming disaster.
Dave B