Previous studies have quantified the amount of variation within and between IAPSO Standard Seawater (SSW) batches through electrical conductivity comparisons by using `Autosal' salinometers (Mantyla, 1980; Mantyla 1986). These studies have shown within-batch differences which are very small, on the order of 0.001. Between-batch differences can be larger and were seen as high as 0.009. This study, made possible by the Hawaii Ocean Time-series (HOT) program, serves to quantify the amount of variation involving some of the more recent SSW batches. In almost all cases, within-batch differences are small, as found earlier on order of 0.001. Between-batch differences exist in these newer batches with differences as large as 0.005.