Thanks for the replies everyone.
I’ve been using a product called K1000 for both diesel and gas. (Not the same - one version for diesel and one version for gas) $25 per quart it’s kinda pricey. The diesel stuff basically keep the gelling down in the winter and helps displace water in my 500 gallon storage tank here on the farm. My Demon and barracuda I dump a little bit in on every fill up and they are good. I must be in a loop on utube or something as I roll past video after video of vapor lock style issues. It just got me thinking- if you can add something to stop this percolation from happening is it the same stuff as what you add to a can to store fuel.