I run mine down and put stabil in it, but I have actually done it both ways with no problems.

Ethanol is Hydroscopic so it will absorb water - I would not leave a tank full of Ethanol "enriched" gas if you can avoid it.

As low as possible.. Then treat it. One other good thing about doing it that way is that if you have the fuel go bad, you have less to have pumped out & disposed of.. ;) Jamie / Lakeside

I run mine as low as possible. Then I pump out the rest with the electric fuel pump and put it in the car or truck.