This is my problem. I have a customer who has an older 1.5 HP above ground pump. It will not hold it's prime and is hard to prime to get started. I took apart the intake and out put and believe there is an air leak in the pump itself. Should I junk it? I have a 3/4 hp submersible to replace it with. The other part is there is no irrigation system. I'm designing and installing that next. This pump was just running 1 fauset and nothing else. I'm going to install a system with 5-7 zones. I'm looking to have 4 or 5 zones of roters and 1 zone of sprays. 1 or 2 zones of drip. I know I need to check my gpm and all that jazz but before I install all of this I was just curious if a 3/4 sub will do the job? And please be gentle!!