Thanks for the replies on my cartridge filter questions. I'll go with the larger model.
Now, I have to decide where to locate a heat pump in the next couple of days. I'll locate it outside with at least 2 feet clearance all sides.
The questions are; does it have to be in full sun? If not will an overhang roof effect performance negatively? If so how about open above but lattice in front? I don't want to have the thing front and centre if I can avoid it. Also how loud are these things?