It is always recommended that you use the same diameter hose/piping as the suction and discharge ports on the pump. While it is sometimes necessary to reduce that diameter, it is NOT recommended that you do so by more than one size. In this case, 1-1/2" hose or piping would be the maximum reduction, While you may see an increased pressure due to the reduced piping, the pump will also see an increased backpressure on the pump. The more you reduce the hose/piping diameter, the more you increase this backpressure AND increase premature pump failure that would NOT be covered under warranty.