I have a little bit of a iron deficiency. normal is between 22-291 i'm at 21. how much mg of sulfate should i take a day?

Try iron rich foods: Because you are just under the normal range, you may want to consider eating more iron-rich foods ( http://www.webmd.com/diet/iron-rich-foods ) rather than taking ferrous sulfate supplements ( http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682778.html ). Consult with your physician after trying either method to have your iron levels rechecked.