I have a Jandy 2hp single speed pump. I have downstream of the pump, a shutoff valve and I find if I turn the shutoff valve so it's about half way closed, and creating some back pressure, the pump seems to run much quieter. There still seems to be the same amount of water coming from the water jets, so I don't think it's reducing the water outflow much. Because the pump is located beside my house, I would like to run it as quietly as possible. So I'm wondering if running the pump this way can damage it, and is this a "normal" behavior for a pump?