I am setting up a 12 r 30 planter for starter fertilizer.  Will travel at about 5.5 mph putting on about 5 gal/acre 10-34-0.  By my calculations it need to put on about .16 gallons per minute/per row of water to equal the 5 gal/ac of 10-34-0 I am shooting for.  I am currently using a 2088 series shurflo electric pump and I did a test run yesterday and with the pump speed maxxed out Iam getting just enough flow to meet my need.  My concern is that when I start pumping fertilizer which is thicker or when some screens get plugged, I will fall short of the output I need.  So Iam looking for a larger 12v pump to replace the one I have now.  Anybody have any recommendations on which pump they prefer?  Iam looking at a Delavan Fat Boy pump http://www.delavanagpumps.com/powerflo/fatboy.htm.  Can this pump be hooked up to a speed varying control rheostat?

Thanks