My 16 year old Whisperflo pump is a bit noisy and leaking quite a bit now. So, because of it's age, decided probably should buy new pump. I keep reading how a 2-speed pump is more efficient, but considering that my sweeper and waterfall both have their own booster/pump, (and no other features used on main pump) I am not sure there would be a reason to ever use more than the one speed on my pump?