We apologize but we feel you have gotten us mixed up with the manufacturer of the product you purchased. We do not make the product or put the options of spreaders on the label, we are just a retail company that provides the products. That being said, as you stated there is no way for any company who makes granular products to list and cover all the thousands of spreaders on the market on the label. You normally have to calibrate your spreader to the product you are using each time by setting it at a medium setting and walking a 1000 sq/ft to see how you get coverage. If you plan to use for example 1.5 lbs per 1000 sq/ft and you put your spreader on a middle setting and walk 1000 sq/ft and run out of product too soon, then you know you have it set too high. If you cover the whole area and still have product left, you have the setting too low. This will help you find the correct setting for your yard and spreader. You can also feel free to call the manufacturer directly to see if anyone there is familiar with the particular spreader model you have. You can reach VPG at 855-270-4776.

Fertilome Lawn Food Plus Iron 24-0-4 should be applied without other fertilizers. You should not over fertilize your lawn. To ensure that your lawn is receiving the proper nutrients, please have a soil sample tested by your local cooperative extension office.

If you are asking if it will cause brown spots in your lawn, it will only harm your lawn if you mis-use it and cause burn by over applying or not following label instructions. If you are asking if it will cause brown patch disease in your lawn, no it will not and if your lawn has a tendency of having brown patch you need to start doing a preventative fungicide application before the signs start appearing.