There's an idea- an old sprayer tank for a mixing pot, or something similar.  A barrel would be cheaper but harder to secure in my nurse truck.  A sprayer tank would have a frame to be tied down with.  I'll have to put some thought into that, especially after I improve the plumbing in the truck box to give me some more room.  I'm going to put a 3-way valve in my suction line to simplify my hosing.  Sometimes moving the pump hoses around inside the little truck box is like wrestling wet alligators while tripping over tool and chemical boxes.  It's an insulated 22' box and seems a little cramped inside at times with a 1300gal legtank, pump, hoses, chems, tools, blocking, etc in there.

 Yep, it was me looking at replacing a Hypro piston pump with something else but didn't really want to go with a roller pump.  I ended up finding a brand new Honda with an Ace centrifugal pump mounted on it for less than I could buy a tiny diaphragm pump with no motor.  Now I've got my original Honda w/ 6-to-1 reducer on it for something else, and that old Hypro is parts for one of the others if/when they break.  The crank is junk though.