I am a true believer in Fleck valves especially the Fleck 5600. On the other hand, I believe the Clack valve is just as good, if not better. You can find a Clack for $750 and a Fleck 5600 for less but the Clack will be more efficient than the standard 5600. I have heard Fleck having problems with the 7000 but may have solved the issues. With 5 people, I think you would be bettered with a 1.5 CF unit.