Depends on whether your state has BioDiesel in all the fuel. Illinois here has Bio in it year round due to a tax kickback for Bio content. Bio stinks in low temps, and it's really hard to keep it from gelling, and even worse the wax fallout problem with cold temps for more than 48 hours. I was using power service and gelled up hard last year, I'm no longer confident (personal opinion of course) that Power Service can help when there is Bio content in the fuel. The diesel shop here tells me Stanadyne additive will help with gelling around here, and that's what I've been using. If I make it through this winter without gelling I'll be even more a believer. So far all the information I could find shows that Stanadyne has done their research and it should be a reliable product.