I was using two at one point actually. One on a closed loop and one for return. The 1" pvc is fine but the noise is rediculous. It sounded like someone had a lawnmower in my living room. Since the tank is right beside my couches, I couldn't handle it. I eventually went to a Mag 24 and am happy with that. A little noise but being submersed and inside a stand kills most of it. Not nearly as much heat transfer either.