i'm using some generic roundup to kill off weeds and grass in a future dove field. the label basically says that performance will be improved with the addition of a surfactat (done) and ammonium sulfate to the diluted mixture in the spray tank. problem is, i can't find amm sulf. i checked the coop and a farm/feed store. i've taken 8 hrs of college chemistry, and know that the molecule breaks up into ions when in water... ammonia and sulfate are floating around in the water. can i substitute epsom salt (magnesium sulfate) and regular household ammonia for ammonium sulfate? if not household ammonia, how about ammonium nitrate (urea)?