I used to spray polymer coatings through a Graco machine. I used a Graco sprayer because the SHUR FLO 12 vt elec motor couldn't handle the thickness of the chemical. Shur Flo is OK... BUT unless that thing's FLUSHED and taken VERY good care of, you'll be changing that 100 dollar pump every three or four months. If you like thirty psi, and three gpm, and a Shur Flo is an option, check out gas powered application. A small honda engine (weed wacker type motor) is all that's needed to spray your chems. For a few hundred, it will make it's money back shortly after usage. Shur Flo, gas powered application, a pump sprayer, the x jet (although the ONLY reason I agree with using the xjet is it KEEPS chems OUT of my hoses and injectors....), or a normal five to one or ten to one injector are all OK to use, take the THICKNESS of the chem you're applying into consideration. If it's thin like water, it won't pose as much pressure through the machine.