These settings are approximate and will vary with ground speed, pattern and slight variations in the equipment. You should ALWAYS calibrate your spreader to ensure proper application. Click here for a great video on how you can calibrate your spreader.
If you have a 50 bag of Newsom fertilizer & you want to cover 10,000 sf, you would need to apply 5 lbs of fertilizer per 1000 sf. (50 lbs divided by 10 = 5)
Using the Earthway 2400 spreader, you would use setting #19