There are many differences in systems. I run a Flo Jet at 60 PSI feeds 4 bays, with the seperate air at 20 PSI, 3/8" Poly T'd above the bay. No needle valves, no foaming chamber. the 20 feet from above the bay to and thru the brush, 3/8 HP Hose allows or foaming, with a 6 hole Erie Brush.