So I am getting a portable natural gas generator in the event that my home loses power, this runs 7500 watts of power off a natural gas hook up. I know this wouldn't be enough to run a 240v hot tub though.

My concern is not that I would want to be able to USE my hot tub during a power outage, but at least be able to keep it from freezing.

My idea is to get an immersion water heater, hook it into an outdoor outlet, then drop it into the hot tub with the cover on.

Think something like this would save me from a frozen tub during the winter? Texas did get down to 10 Farenheit a couple years ago, but we regularly see 25-35 degree temps in the winter. So not like I'm living in Canada wondering if this would work or not...

Here is the product:

https://www.amazon.com/Immersion-Gesail-Submersible-Thermostat-Protection/dp/B07JB235C2/