Good morning, Joe. You may have seen my post a few days ago about this on the DeFever Cruisers' Forum. My advice was to add a half cup of Cascade powdered dishwashing detergent to each head once a week, clean each with it and flush. According to Fleet Repair and Marine in Ft. Myers, this is what they recommend to their clients with Vacuflush systems to keep their hoses from building up calcium deposits, etc. Bob Shircliff Captain Bob's Yacht Service, LLC Professional Yacht Delivery and Teaching Captain www.captbobsyachtservice.com Follow Us On Facebook www.facebook.com/captbobsyachtservice (502) 939-9045