Loading the mixing tanks and mixing chemicals is a drag. I am looking at installing a siphoning system on my spray truck. The one I am looking at installs at the end of the hose before the gun. I need to know how much pressure is at the end of the hose. I know my pressure at the pump is 200 psi. How much is at the end of 300' of 1/2" hose? My cheap (non water filled) gage shows 200 psi at the end of the hose. When I drop the pressure at the pump to read 100 psi, my cheap gage shows 140 psi. Obviously the cheap gage has got to go. I'll get a water filled gage this week. In the mean time, does anybody care to speculate on how much pressure is dropped by 300' of 1/2" hose? Does anybody have a formula?