Hello. Like you I have really hard water. Its michigan well water and comes out of the tap at around 400-415 ppm. I recently bought 2 filters. One is a charcoal type in-line and the other is a basic in-line particulate filter. With both in use my water comes out at about 200 ppm. When I started my ebb system I ran with around 600 ppm total. Every thing seemed OK.Hope this helps.:thumbsup: