I had a 3/4 hp submersible pump go out rated at 10gpm I have a spare 1/2 hp 10gpm pump. My question is will there be much differance in the two? I use it to water lawn from a lake I ran 500ft of 1 in. pipe from water to sprinklers but the elevation rise is only about 60 ft. With the 3/4 I was getting 10-13gpm at sprinklers do you think the 1/2 will take care of what I need or do I need another 3/4hp. I run the pump open no pressure tank.