i have a couple of Gould pums 1.5 hp we use them to pump water out of out pond for irrigation. they are desinged for continous use. we have a 2.5 " line that goes into our pond about 55 feet from pump to pond then we have about 5 miles of pipe to irrigate our nursery. why cant one of these pumps be used to creat vacume in my sap lines. what info do i not know?

Adam