I have some old gas probably 3 years old in a above ground elevated storage tank. The tank probably has 50 gallons in it is it safe to use? Should I add something to it or blend it with 50-50 new and old gas. Or is there a additive that a person could put in it?
I've burnt older gas than that, but that's in a carb'd vehicle. It wouldn't be a bad idea to dilute 50/50 or lower, and run it through a sediment and water filter, because there's probably condensation in there by now.
Drain out any water at the bottom and it should be fine to mix. If it had ethanol in it, the water and ethanol should come off the bottom together, leaving the gasoline on top. There are additives to preserve gas, but they have to be added first, not now.