Lesco told me 13 is the average setting on the pg magnum for merit @ 70 lbs. acre. This is at slow speed. Did not have a setting avaliable for high speed. My questions is that seems really high for the slow speed. Even at high speed that still seems high. It is such a small particle. I have calibrated over and over with my ferts and have them all very close. You guys who throw merit .5g with a pg magnum is this close or way off. I tried their web site but merit spreader setting are not available.