Can it be done? We are filtering Spartan EP 460 gear oil. After analysis we are finding that the filter process is removing the contaminants we want, but is reducing our boron levels as well. Analysis of a virgin sample and a sample of virgin oil filtered shows we are starting with 19ppm of boron and after filtering it drops to 11ppm. We're looking at way to add boron back to the oil but not add any silly ingedients we don;t need or want. Thanks!