How much detergent should I use depending on my water hardness?

For soft water (0–3 grains), use half a cup in the main dispenser; for medium water (3–7 grains), use a full main cup; and for hard water (7–12 grains), fill the main cup completely and add detergent to the open cup as well. Water with 12 or more grains is extremely hard and a water softener is recommended, as lime can build up in the water valve and cause flooding. The filled main cup holds 3 tablespoons and the filled open cup holds 2 tablespoons. (Page 7)