This Kubota lube would be worth knowing about. I've used Stanadyne Performance fuel treatment for many years and have looked for Opti-Lube --but can't find it--so Kubota might be worth consideration. This diesel low sulfer protection thing seems like a dark science that is a big secret. There are a lot of products of widely varying prices and claims all over the board. Sure we had a diesel guy here or maybe DieselPower could come back for some comments on what works and why.