The influence of Ni-Y catalyst composition on the bulk scale synthesis of single-walled carbon nanotubes (SWNTs) is studied using solution phase near-infrared spectroscopy. We found that a wide range of catalyst concentrations (3-6 atom % Ni and 1-2 atom % Y), allow efficient production of high-purity as-prepared (AP-) SWNT soot. The broad window of acceptable synthetic parameters found in this study suggests that there is an opportunity to scale-up the electric arc (EA) discharge synthesis of SWNTs to the industrial level. Significant deviations of the concentrations of either Ni or Y outside the optimum parameters result in a degradation in the quality and yield of the AP-SWNT soot.