These three 30 cubic foot each water softeners service the boiler make-up water. There is a Cla-Val to blend the soft water to create a 3 grain hardness, per the Marriott instructions. These three units were plumbed into a 6″ mainline manifold down to 2″ line, three times. The plumbing was very complicated and quite impressive. The valves used were alternating Fleck 9000 2″ valves. The installation was done by Mountain Slope Water and was completed over a period of approximately 5 days.